VueJS

Vue 3 Composition API, do you really need it?

Published Mar 4, 2020

Updated May 30, 2023

12 min read

This article was written over 18 months ago and may contain information that is out of date. Some content may be relevant but please refer to the relevant official documentation or available resources for the latest information.

Oh What a New Vue!

The Vue team has announced that version 3 of the Vue framework will be released during Q1 2020.

The new framework is expected to bring a number of advancements, most of which target the framework core itself, while maintaining the standard syntax for building Vue apps to which we have become accustomed. Essentially,the codebase is rewritten, and the framework is changed.

With new features in JavaScript, the opportunity to rewrite was seized. Additionally, they incorporated developer feedback and ideas to the framework, and it shows. The result is a much more performant framework.

Developers will notice an improvement in the framework performance without having to dig into the source code to adjust it. Thank them later when you discover just how much heartache this saves you!

Below is a brief summary of the things that will change in Vue 3:

Virtual DOM rewrite for better performance, and improved TypeScript support.
Exposed Reactivity API.
Time Slicing Support.
Static Tree Hoisting.
Optimized Slots Generations.
Monomorphic Calls.

We will focus on the new Vue 3 Composition API. This API is fully optional, however, you can easily integrate it, and benefit from it in your app.

To stay in the loop on the Vue 3 roadmap, I highly recommend you keep checking this website Vue 3 – A roundup of infos about the new version of Vue.js

Vue Components / Ways to build them

The new Composition API is Vue’s approach to building Components in Vue 3. Using the Component Options API has been the traditional way of building components adopted in Vue 2.

A component has several options that a developer can use to implement a certain feature inside the component. With several options, a developer can use, and implement a certain feature inside the component.

Component Options API / Traditional method

For instance, your app has a feature to display a list of products and allow the user to execute Create Read Update Delete (CRUD) operations on them.

One of the possible ways to implement this feature in a Vue 2 component is to define the following script code:

<template>
  <div>Products</div>
</template>

<script>
export default {
  data() {
    return {
      products: [],
      product: null,
    };
  },
  methods: {
    createProduct() {
      // create product
    },
    updateProduct() {
      // update product
    },
    deleteProduct() {
      // delete product
    },
  },
};
</script>

The Component Options API refers to the artifacts that a Vue 2 component offers to help you implementing a certain feature in your app.

The data option is used to define an array of product items to display, and a single product object to track selected or new products.

The methods option is used to define any custom function or method you need to use in the component. There are other options too like computed, watch, etc.

This has been the traditional way of building components in Vue 2.

This approach works well for small or even medium apps. The problems emerge when the app grows to a few thousand components. Typically, your entire app won’t be built with a few components only. The best approach has been to compose your app out of smaller components. This has many benefits in terms of testing, readability, and code maintenance.

In other words, with more features implemented, the components become convoluted and difficult to track. Moreover, the Options API has limits on code reuse and sharing. Shared functionalities have to be repeated over and over again throughout your components.

The Component Options API itself introduces confusion to developers. Think of it this way; if you want to build a single feature, you have to scatter it among the different options (props, data, watch to name a few). As components are growing in size as well as function, the features are scattered across the options inside a component.

A hot mess!

Component Options API and Mixins

The Component Options API doesn’t promote code reuse or share. This adds to its complexity when using it.

One solution to mitigate around the complexity is to build components with the help of mixins.

We still have to deal with the fact that features' implementations are spread over several options. However, now with mixins, you can enhance your components by employing more code reuse and sharing common functionalities inside mixins.

Vue mixins allow you to refactor your common code inside a mixin file. Then, you can import this mixin to any component that needs to use this common code.

This is a step in the right direction, to solving the problem of code reuse in Vue 2 apps, but it’s not the end all and be all. Why?

A mixin follows the same standards of the Composition Options API. Let’s refactor the component shown before making use of mixins:

<template>
  <div>Products</div>
</template>

<script>
import ProductsMixin from "@/mixins/Products.mixin";

export default {
  mixins: [ProductsMixin],
};
</script>

Almost all of the code in the component has been stripped out.

A ProductsMixin is now imported into the component. To let the component know and use this mixin, you add the mixin into the mixins option array.

The ProductsMixin looks like this:

export default {
  data() {
    return {
      products: [],
      product: null
    };
  },
  methods: {
    createProduct() {
      // create product
    },
    updateProduct() {
      // update product
    },
    deleteProduct() {
      // delete product
    }
  }
};

The mixin exports a default ES6 object that uses the Component Options API to layout its code. Looking at a mixin file reminds me of a Vue component. The same structure and organization!

I’ve removed the data and methods options from inside the component, and placed them inside the mixin.

At runtime, the Vue framework will merge the component code, and the mixin code, to produce a single component with options coming from the two sources.

You can import this mixin to other components in your app where they need to offer Products CRUD operations.

Using a mixin comes at a cost:

Naming conflicts.
The complexity of the Component Options API is inherited.
Complexity in tooling. With mixins, you always have to open the mixin file and check the names of methods or data properties before using them. The auto-merging happens behind the scenes at runtime. Therefore, there is no way to have intelligence inside the components for mixins fields.

Things to keep in mind when using Vue mixins:

Life cycle hooks run first for mixins then for components.
Options from both components and mixins will be merged at runtime.
The components options will take priority when there are conflicting keys in these objects (methods, data, etc.)

Using the Composition API

The Composition API introduces a new approach to building components, and implementing features in them.

Let’s see how the aforementioned component with the mixin example can be converted to the Composition API approach.

First, let’s look at the Products component:

<template>
  <div>
    <div
      v-for="p in products"
      :key="p.id"
    >Product Name: {{ p.name }} - Product Price: ${{ p.price }}</div>
    <div>
      <button @click="createAProduct">Create New</button>
    </div>
  </div>
</template>

<script>
import { useProducts } from "@/cmp-functions/Products";

export default {
  name: "Products",
  setup() {
    return {
      ...useProducts()
    };
  },
  methods: {
    createAProduct() {
      this.createProduct({
        id: Math.floor(Math.random() * 10) + new Date().getTime(),
        name: "New Product",
        price: Math.floor(Math.random() * 1000).toString()
      });
    }
  }
};
</script>

The most remarkable section of the component is the setup() function. It is added by the new Vue 3 Composition API. Vue is aware of it, and will run it before even creating the component object itself. Hence, this explains why the object this, that refers to the component itself, is not available inside the function.

Inside this function, you define the data properties, computed methods, watch methods, normal methods and any other utility methods needed for your code. It should expose and return an object containing all the public methods and data properties. By public, we mean anything you want shared and used by the Vue component itself.

In our case, the function returns an object by spreading the useProducts() function. In the Vue 3 Composition API terminology, useProducts() is a Composition Function, and returns an object.

The setup() function returns an object containing all data properties and methods returned by useProducts() function.

The useProducts() function is defined inside the file /src/cmp-functions/Products.js as follows:

import { ref } from "@vue/composition-api";

export const useProducts = () => {
  const products = ref([]);

  const createProduct = ({ id, name, price }) => {
    products.value.push({ id, name, price });
  };

  const updateProduct = ({ id, name, price }) => {
    const itemIndex = products.value.findIndex(p => p.id === id);

    if (itemIndex < 0) {
      return;
    }

    products.value.splice(itemIndex, 1, { id, name, price });
  };

  const deleteProduct = id => {
    const itemIndex = products.value.findIndex(p => p.id === id);

    if (itemIndex < 0) {
      return;
    }

    products.value.splice(itemIndex, 1);
  };

  return {
    createProduct,
    updateProduct,
    deleteProduct,
    products
  };
};

Start by importing ref function from the @vue/composition-api package. It wraps any value or object, and makes it reactive so that if its value changes, Vue is aware of its presence, and it will update the UI accordingly.

The useProducts() function is a normal JavaScript function (arrow function in our case). It returns an object.

Inside the function, we define the products reactive data property with an initial value of an empty array.

Without the use of ref([]), Vue won’t be able to detect changes to the array, and the UI can’t be updated.

The rest of the functions createProduct(), updateProduct(), and deleteProduct() are just JavaScript functions to handle the CRUD operations on Products.

Notice the use of products.value when interacting with reactive data properties. This syntax is only required inside the composition function. When using the data properties inside a Vue component, whether for data set or get, you refer to the name of the data property without the need to use the .value syntax. This syntax is only used inside the composition function.

Finally, the useProducts() functions return an object with the list of data properties and methods to expose and are available to the Vue Component.

A composition function returns a whitelisted list of data properties and methods to the Vue component. It can define as much as it needs to form private data properties and methods, without exposing them to the Vue component. You expose whatever is needed to run the feature you are building.

You can move the code from inside the useProducts() function to the body of the setup() function inside the component. This is absolutely legit. However, from the code reuse perspective, it’s recommended to move out a single composition function into its own JavaScript file.

Now back to the Vue component, the setup() function returns the same list of data properties and methods returned by the composition function. The Vue component treats those properties and methods as if they were defined on the component itself. Inside the component template you can bind to the data properties and methods defined inside the setup() function.

One cannot help but notice the many advantages the Composition API brings on such as:

A composition function or setup() function doesn’t follow the Component Options API. Hence, a feature can be implemented as a single composition function, or even as one block inside the setup() function. There’s no need to spread a feature implementation anymore among the component options. You can put together data properties, private methods, public methods, computed properties, watch methods and others.

To any vanilla JavaScript developer, a composition function looks very familiar. Nothing is special about it. Just a usual JavaScript function. The tooling experience has been improved. Now you specify exactly what you are returning from any composition function. This is compared to the auto-magic that was happening at runtime when mixins options were merged with the component options.

Better and clear code reuse and sharing. Each and every feature is now implemented in its own composition function or JavaScript file.

Demo

Now that you have the theory down on the new Vue Composition API, let's look at how to develop a basic Vue 2 app that contains two views:

The first is the Download Image view that allows the user to view and download an image file. The second is the Download Pdf view that allows the user to view and download a PDF file.

I will first build this app following the traditional Vue Component Options API method. Then, I will enhance this method to make use of Mixins for code reuse. Finally, I will convert this app to make use of the new Vue Composition API.

Start by cloning the app source code from the following GitHub repo git@github.com:bhaidar/vue3-composition-api.git.

Once done, switch to the dev* branch, and run the following commands in order to start the app.

npm i
npm run serve

The app navigation bar allows you to switch between the two available views.

Traditional Vue Components / Options API

the complete solution with duplicated components code can be found at feat/repeated-inside-components branch

To build the download file feature, I am going to implement this feature in both Views separately. The implementation will be similar in both components, hence, I will show you only one of the implementations.

Replace the content of the DownloadPdf.vue file with the following:

<template>
  <div class="download-pdf">
     <DownloadFileButton link="Download Pdf File" @download-file-btn="downloadPdf('dummy.pdf')" />
      <embed src="/assets/dummy.pdf" type="application/pdf">
  </div>
</template>

<script>
import axios from '@/http-common.js';
import DownloadFileButton from '@/components/DownloadFileButton.vue';

export default {
  data() {
    return {
      status: {
        showSpinner: false,
        showSuccess: false,
        showErrors: false,
      },
    };
  },
  components: {
    DownloadFileButton,
  },
  methods: {
    downloadPdf(fileName) {
      this.status = { ...this.status, showSpinner: true };

      axios.get(`/assets/${fileName}`, {
        responseType: 'arraybuffer',
        headers: {
          Accept: 'application/pdf',
        },
      }).then((response) => {
        this.status = { ...this.status, showSpinner: false, showSuccess: true };

        const arrayBufferView = new Uint8Array(response.data);
        const blob = new Blob([arrayBufferView], {
          type: 'application/pdf',
        });
        const urlCreator = window.URL || window.webkitURL;
        const fileUrl = urlCreator.createObjectURL(blob);
        const fileLink = document.createElement('a');
        fileLink.href = fileUrl;
        fileLink.setAttribute('download', `${this.randomNumber()}-${fileName}`);
        document.body.appendChild(fileLink);
        fileLink.click();
      }).catch(() => {
        this.status = { ...this.status, showSpinner: false, showErrors: true };
      });
    },
    randomNumber() {
      return Math.floor(Math.random() * 100);
    },
  },
};
</script>

The component defines some data options to track the download process, and display feedback accordingly.

The downloadPdf() method makes use of axios HTTP Client to request the PDF file from the server. Once the file content is available, it creates a Hyperlink element with a URL pointing to a blob Url of the file downloaded, and simulates a click event on the link so that the file is forced to download inside the browser.

In a real-life example, you would most probably have a backend API that will handle downloading files.

The same code is repeated inside the DownloadImage.vue view. The same code is repeated without any code reuse or sharing.

Let’s see how we can improve on this code by introducing mixins.

Using Mixins in Components

the complete solution with mixins can be found at feat/using-mixins branch

I will now refactor the repeated code inside the views into a single mixin file. Add a new mixin under the path /src/mixins/DownloadFile.mixin.js. Place the following content inside this new file:

import axios from '@/http-common.js';

export default {
  data() {
    return {
      status: {
        spinner: false,
        sucess: false,
        errors: null,
      },
    };
  },
  computed: {
    showSpinner() {
      return this.status.spinner;
    },
    showSuccess() {
      return this.status.success;
    },
    showErrors() {
      return this.status.errors;
    },
  },
  methods: {
    async downloadFile(fileName, contentType) {
      this.status = { ...this.status, spinner: true };

      axios.get(`/assets/${fileName}`, {
        responseType: 'arraybuffer',
        headers: {
          Accept: contentType,
        },
      }).then(value => new Promise(resolve => setTimeout(resolve, 2000, value)))
        .then((response) => {
          const blobResults = this.getBlobResults(response.data, contentType);
          const blobFileUrl = this.createBlobFileUrl(blobResults);
          const fileLink = this.generateFileLink(fileName, blobFileUrl);

          this.status = { ...this.status, spinner: false, success: true };

          // Download file
          fileLink.click();
        }).catch((err) => {
          this.status = { ...this.status, spinner: false, errors: err };
        });
    },
    createBlobFileUrl(blob) {
      const urlCreator = window.URL || window.webkitURL;
      return urlCreator.createObjectURL(blob);
    },
    generateFileLink(fileName, blobUrl) {
      const fileLink = document.createElement('a');

      fileLink.href = blobUrl;
      fileLink.setAttribute('download', `${this.randomNumber()}-${fileName}`);

      document.body.appendChild(fileLink);

      return fileLink;
    },
    getBlobResults(fileContent, contentType) {
      const arrayBufferView = new Uint8Array(fileContent);
      return new Blob([arrayBufferView], {
        type: contentType,
      });
    },
    randomNumber() {
      return Math.floor(Math.random() * 100);
    },
    wait(ms, value) {
      return new Promise(resolve => setTimeout(resolve, ms, value));
    },
  },
};

The code is now more modularized, and split into smaller and readable functions. The same data properties have been defined inside this mixin. In addition, a new generic method, the downloadFile() is defined to cater for any file download.

Switch back to the DownloadPDF.vue view, and update the component by pasting:

<template>
  <div class="download-pdf">
     <DownloadFileButton link="Download Pdf File" @download-file-btn="downloadPdf('dummy.pdf')" />

     <div class="download-image__results">
        <span v-if="showSpinner" class="spinner">Downloading ...</span>
        <span v-if="showSuccess" class="success">File downloaded successfully!</span>
        <span v-if="showErrors" class="failure">File failed to download!</span>
      </div>

      <embed src="/assets/dummy.pdf" type="application/pdf">
  </div>
</template>

<script>
import DownloadFileMixin from '@/mixins/DownloadFile.mixin';
import DownloadFileButton from '@/components/DownloadFileButton.vue';

export default {
  mixins: [DownloadFileMixin],
  components: {
    DownloadFileButton,
  },
  methods: {
    downloadPdf(fileName) {
      this.downloadFile(fileName, 'application/pdf');
    },
  },
};
</script>

The component is now more concise. It imports the DownloadFile.mixin.js file, and injects it into the mixins option of the Vue component.

A message is now shown to signal the starting, success and failure stages of the file download.

The mixin exposes a single method, the downloadFile(). The component calls this method to download the PDF file.

Finally, let’s improve on the code and introduce the Vue Composition API.

Using Composition API

the complete solution with mixins can be found at feat/composition-api branch

To start using the Vue 3 Composition API you don’t have to wait until Vue 3 is released. The Vue team made available the Composition API for any Vue 2 app.

Add the Composition API to your app by installing the following NPM package:

npm install --save @vue/composition-api

Once the library is installed, go to the main.js file inside your app folder, and add the code to tell Vue to use this library or plugin.

import Vue from 'vue';
import VueCompositionApi from '@vue/composition-api';
import App from './App.vue';
import router from './router';

Vue.config.productionTip = false;

Vue.use(VueCompositionApi);

new Vue({
  router,
  render: h => h(App),
}).$mount('#app');

That’s all! Now you can start using the Composition API in your app.

Let’s add a new composition function under the path /src/cmp-functions/download-file.js. Replace its content with the following:

/* eslint-disable import/prefer-default-export */
import { ref, computed } from '@vue/composition-api';
import axios from '@/http-common.js';

export const useDownloadFile = () => {
  const status = ref({
    spinner: false,
    success: false,
    errors: null,
  });

  const randomNumber = () => Math.floor(Math.random() * 100);

  const showSpinner = computed(() => status.spinner);

  const showSuccess = computed(() => status.success);

  const showErrors = computed(() => status.errors);

  const createBlobFileUrl = (blob) => {
    const urlCreator = window.URL || window.webkitURL;
    return urlCreator.createObjectURL(blob);
  };

  const generateFileLink = (fileName, blobUrl) => {
    const fileLink = document.createElement('a');

    fileLink.href = blobUrl;
    fileLink.setAttribute('download', `${randomNumber()}-${fileName}`);

    document.body.appendChild(fileLink);

    return fileLink;
  };

  const getBlobResults = (fileContent, contentType) => {
    const arrayBufferView = new Uint8Array(fileContent);
    return new Blob([arrayBufferView], {
      type: contentType,
    });
  };

  const downloadFile = async (fileName, contentType) => {
    status.value = { spinner: true, success: false, errors: null };

    axios.get(`/assets/${fileName}`, {
      responseType: 'arraybuffer',
      headers: {
        Accept: contentType,
      },
    }).then(value => new Promise(resolve => setTimeout(resolve, 2000, value)))
      .then((response) => {
        const blobResults = getBlobResults(response.data, contentType);
        const blobFileUrl = createBlobFileUrl(blobResults);
        const fileLink = generateFileLink(fileName, blobFileUrl);

        status.value = { spinner: false, success: true, errors: null };

        // Download file
        fileLink.click();
      }).catch((err) => {
        status.value = { spinner: false, success: false, errors: err};
      });
  };

  return {
    showSpinner, showSuccess, showErrors, downloadFile,
  };
};

The code should be familiar to you by now. The only new thing you see is the definition of some computed properties.

You define a new computed property inside the Composition API by using the computed() function. This function accepts a callback function that should return a value. This is the value of the computed property. It, as you know from Vue 2, it will track any change to the underlying data properties, and will run accordingly.

The useDownloadFile() composition function makes use of several private functions. It only exposes what’s needed by the Vue component and not by exposing all the implementation.

That’s it for the composition function.

Let’s go back to the DownloadPdf.vue view to import this function and make use of it. Replace the content of the view with the following:

<template>
  <div class="download-pdf">
     <DownloadFileButton link="Download Pdf File"
      @download-file-btn="downloadFile('dummy.pdf', 'application/pdf')" />

     <div class="download-image__results">
        <span v-if="showSpinner" class="spinner">Downloading ...</span>
        <span v-if="showSuccess" class="success">File downloaded successfully!</span>
        <span v-if="showErrors" class="failure">File failed to download!</span>
      </div>

      <embed src="/assets/dummy.pdf" type="application/pdf">
  </div>
</template>

<script>
import { useDownloadFile } from '@/cmp-functions/download-file';
import DownloadFileButton from '@/components/DownloadFileButton.vue';

export default {
  components: {
    DownloadFileButton,
  },
  setup() {
    const {
      showSpinner, showSuccess, showErrors, downloadFile,
    } = useDownloadFile();

    return {
      showSpinner, showSuccess, showErrors, downloadFile,
    };
  },
};
</script>

The component imports the useDownloadFile() composition function. It extracts the computed properties and the downloadFile() method from the composition function and returns them from inside the setup() function.

To download a file, the component calls on the downloadFile(‘dummy.pdf’, ‘application/pdf’) method, passing over the name of the PDF file to download and the file’s content type. To show download progress, the component binds the UI to the computed properties, defined by the composition function.

Conclusion

The Vue 3 Composition API is optional!

I am pretty sure you can see the value and benefit when using the new Vue 3 Composition API. The most remarkable enhancement, in my opinion, is building a single feature in a single composition function without the need to spread the implementation among the Vue options (Options API).

In addition, the new tooling experience and intellisense make it easier to see what you are importing from the composition function, and also what you are exposing to your Vue component. This brings an incredible experience while coding.

Whether you start using the new Composition API in your apps will depend on what you want to achieve.

I definitely recommend using the new API in much larger apps with many components where code reuse and sharing is necessary!

Similarly, if you are fed up with the Component Options API and the notion of building a feature by spreading it over the different available options, it’s time to start using this new API!

Happy vueing!

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About the author(s)

Bilal Haidar
Author, Developer, and Mentor: Professional ASP.NET 3.5 Security, Membership, and Role Management with C# and VB | A Complete Guide to VueJS
@bhaidar @bhaidar

Introduction to Zod for Data Validation

As web developers, we're often working with data from external sources like APIs we don't control or user inputs submitted to our backends. We can't always rely on this data to take the form we expect, and we can encounter unexpected errors when it deviates from expectations. But with the Zod library, we can define what our data ought to look like and parse the incoming data against those defined schemas. This lets us work with that data confidently, or to quickly throw an error when it isn't correct. Why use Zod? TypeScript is great for letting us define the shape of our data in our code. It helps us write more correct code the first time around by warning us if we are doing something we shouldn't. But TypeScript can't do everything for us. For example, we can define a variable as a string or a number, but we can't say "a string that starts with user_id_ and is 20 characters long" or "an integer between 1 and 5". There are limits to how much TypeScript can narrow down our data for us. Also, TypeScript is a tool for us developers. When we compile our code, our types are not available to the vanilla JavaScript. JavaScript can't validate that the data we actually use in our code matches what we thought we'd get when we wrote our TypeScript types unless you're willing to manually write code to perform those checks. This is where we can reach for a tool like Zod. With Zod, we can write data schemas. These schemas, in the simplest scenarios, look very much like TypeScript types. But we can do more with Zod than we can with TypeScript alone. Zod schemas let us create additional rules for data parsing and validation. A 20-character string that starts with user_id_? It's z.string().startsWith('user_id_').length(20). An integer between 1 and 5 inclusive? It's z.number().int().gte(1).lte(5). Zod's primitives give us many extra functions to be more specific about *exactly* what data we expect. Unlike TypeScript, Zod schemas aren't removed on compilation to JavaScript—we still have access to them! If our app receives some data, we can verify that it matches the expected shape by passing it to your Zod schema's parse function. You'll either get back your data in exactly the shape you defined in your schema, or Zod will give you an error to tell you what was wrong. Zod schemas aren't a replacement for TypeScript; rather, they are an excellent complement. Once we've defined our Zod schema, it's simple to derive a TypeScript type from it and to use that type as we normally would. But when we really need to be sure our data conforms to the schema, we can always parse the data with our schema for that extra confidence. Defining Data Schemas Zod schemas are the variables that define our expectations for the shape of our data, validate those expectations, and transform the data if necessary to match our desired shape. It's easy to start with simple schemas, and to add complexity as required. Zod provides different functions that represent data structures and related validation options, which can be combined to create larger schemas. In many cases, you'll probably be building a schema for a data object with properties of some primitive type. For example, here's a schema that would validate a JavaScript object representing an order for a pizza: ` Zod provides a number of primitives for defining schemas that line up with JavaScript primitives: string, number, bigint, boolean, date, symbol, undefined, and null. It also includes primitives void, any, unknown, and never for additional typing information. In addition to basic primitives, Zod can define object, array, and other native data structure schemas, as well as schemas for data structures not natively part of JavaScript like tuple and enum. The documentation contains considerable detail on the available data structures and how to use them. Parsing and Validating Data with Schemas With Zod schemas, you're not only telling your program what data should look like; you're also creating the tools to easily verify that the incoming data matches the schema definitions. This is where Zod really shines, as it greatly simplifies the process of validating data like user inputs or third party API responses. Let's say you're writing a website form to register new users. At a minimum, you'll need to make sure the new user's email address is a valid email address. For a password, we'll ask for something at least 8 characters long and including one letter, one number, and one special character. (Yes, this is not really the best way to write strong passwords; but for the sake of showing off how Zod works, we're going with it.) We'll also ask the user to confirm their password by typing it twice. First, let's create a Zod schema to model these inputs: ` So far, this schema is pretty basic. It's only making sure that whatever the user types as an email is an email, and it's checking that the password is at least 8 characters long. But it is *not* checking if password and confirmPassword match, nor checking for the complexity requirements. Let's enhance our schema to fix that! ` By adding refine with a custom validation function, we have been able to verify that the passwords match. If they don't, parsing will give us an error to let us know that the data was invalid. We can also chain refine functions to add checks for our password complexity rules: ` Here we've chained multiple refine functions. You could alternatively use superRefine, which gives you even more fine grained control. Now that we've built out our schema and added refinements for extra validation, we can parse some user inputs. Let's see two test cases: one that's bound to fail, and one that will succeed. ` There are two main ways we can use our schema to validate our data: parse and safeParse. The main difference is that parse will throw an error if validation fails, while safeParse will return an object with a success property of either true or false, and either a data property with your parsed data or an error property with the details of a ZodError explaining why the parsing failed. In the case of our example data, userInput2 will parse just fine and return the data for you to use. But userInput1 will create a ZodError listing all of the ways it has failed validation. ` ` We can use these error messages to communicate to the user how they need to fix their form inputs if validation fails. Each error in the list describes the validation failure and gives us a human readable message to go with it. You'll notice that the validation errors for checking for a valid email and for checking password length have a lot of details, but we've got three items at the end of the error list that don't really tell us anything useful: just a custom error of Invalid input. The first is from our refine checking if the passwords match, and the second two are from our refine functions checking for password complexity (numbers and special characters). Let's modify our refine functions so that these errors are useful! We'll add our own error parameters to customize the message we get back and the path to the data that failed validation. ` Now, our error messages from failures in refine are informative! You can figure out which form fields aren't validating from the path, and then display the messages next to form fields to let the user know how to remedy the error. ` By giving our refine checks a custom path and message, we can make better use of the returned errors. In this case, we can highlight specific problem form fields for the user and give them the message about what is wrong. Integrating with TypeScript Integrating Zod with TypeScript is very easy. Using z.infer<typeof YourSchema> will allow you to avoid writing extra TypeScript types that merely reflect the intent of your Zod schemas. You can create a type from any Zod schema like so: ` Using a TypeScript type derived from a Zod schema does *not* give you any extra level of data validation at the type level beyond what TypeScript is capable of. If you create a type from z.string.min(3).max(20), the TypeScript type will still just be string. And when compiled to JavaScript, even that will be gone! That's why you still need to use parse/safeParse on incoming data to validate it before proceeding as if it really does match your requirements. A common pattern with inferring types from Zod schemas is to use the same name for both. Because the schema is a variable, there's no name conflict if the type uses the same name. However, I find that this can lead to confusing situations when trying to import one or the other—my personal preference is to name the Zod schema with Schema at the end to make it clear which is which. Conclusion Zod is an excellent tool for easily and confidently asserting that the data you're working with is exactly the sort of data you were expecting. It gives us the ability to assert at runtime that we've got what we wanted, and allows us to then craft strategies to handle what happens if that data is wrong. Combined with the ability to infer TypeScript types from Zod schemas, it lets us write and run more reliable code with greater confidence....

Nov 15, 2024

7 mins

JavaScriptZod

Exploring Angular Forms: A New Alternative with Signals

Exploring Angular Forms: A New Alternative with Signals In the world of Angular, forms are essential for user interaction, whether you're crafting a simple login page or a more complex user profile interface. Angular traditionally offers two primary approaches: template-driven forms and reactive forms. In my previous series on Angular Reactive Forms, I explored how to harness reactive forms' power to manage complex logic, create dynamic forms, and build custom form controls. A new tool for managing reactivity - signals - has been introduced in version 16 of Angular and has been the focus of Angular maintainers ever since, becoming stable with version 17. Signals allow you to handle state changes declaratively, offering an exciting alternative that combines the simplicity of template-driven forms with the robust reactivity of reactive forms. This article will examine how signals can add reactivity to both simple and complex forms in Angular. Recap: Angular Forms Approaches Before diving into the topic of enhancing template-driven forms with signals, let’s quickly recap Angular's traditional forms approaches: 1. Template-Driven Forms: Defined directly in the HTML template using directives like ngModel, these forms are easy to set up and are ideal for simple forms. However, they may not provide the fine-grained control required for more complex scenarios. Here's a minimal example of a template-driven form: ` ` 2. Reactive Forms: Managed programmatically in the component class using Angular's FormGroup, FormControl, and FormArray classes; reactive forms offer granular control over form state and validation. This approach is well-suited for complex forms, as my previous articles on Angular Reactive Forms discussed. And here's a minimal example of a reactive form: ` ` Introducing Signals as a New Way to Handle Form Reactivity With the release of Angular 16, signals have emerged as a new way to manage reactivity. Signals provide a declarative approach to state management, making your code more predictable and easier to understand. When applied to forms, signals can enhance the simplicity of template-driven forms while offering the reactivity and control typically associated with reactive forms. Let’s explore how signals can be used in both simple and complex form scenarios. Example 1: A Simple Template-Driven Form with Signals Consider a basic login form. Typically, this would be implemented using template-driven forms like this: ` ` This approach works well for simple forms, but by introducing signals, we can keep the simplicity while adding reactive capabilities: ` ` In this example, the form fields are defined as signals, allowing for reactive updates whenever the form state changes. The formValue signal provides a computed value that reflects the current state of the form. This approach offers a more declarative way to manage form state and reactivity, combining the simplicity of template-driven forms with the power of signals. You may be tempted to define the form directly as an object inside a signal. While such an approach may seem more concise, typing into the individual fields does not dispatch reactivity updates, which is usually a deal breaker. Here’s an example StackBlitz with a component suffering from such an issue: Therefore, if you'd like to react to changes in the form fields, it's better to define each field as a separate signal. By defining each form field as a separate signal, you ensure that changes to individual fields trigger reactivity updates correctly. Example 2: A Complex Form with Signals You may see little benefit in using signals for simple forms like the login form above, but they truly shine when handling more complex forms. Let's explore a more intricate scenario - a user profile form that includes fields like firstName, lastName, email, phoneNumbers, and address. The phoneNumbers field is dynamic, allowing users to add or remove phone numbers as needed. Here's how this form might be defined using signals: ` > Notice that the phoneNumbers field is defined as a signal of an array of signals. This structure allows us to track changes to individual phone numbers and update the form state reactively. The addPhoneNumber and removePhoneNumber methods update the phoneNumbers signal array, triggering reactivity updates in the form. ` > In the template, we use the phoneNumbers signal array to dynamically render the phone number input fields. The addPhoneNumber and removePhoneNumber methods allow users to reactively add or remove phone numbers, updating the form state. Notice the usage of the track function, which is necessary to ensure that the ngFor directive tracks changes to the phoneNumbers array correctly. Here's a StackBlitz demo of the complex form example for you to play around with: Validating Forms with Signals Validation is critical to any form, ensuring that user input meets the required criteria before submission. With signals, validation can be handled in a reactive and declarative manner. In the complex form example above, we've implemented a computed signal called formValid, which checks whether all fields meet specific validation criteria. The validation logic can easily be customized to accommodate different rules, such as checking for valid email formats or ensuring that all required fields are filled out. Using signals for validation allows you to create more maintainable and testable code, as the validation rules are clearly defined and react automatically to changes in form fields. It can even be abstracted into a separate utility to make it reusable across different forms. In the complex form example, the formValid signal ensures that all required fields are filled and validates the email and phone numbers format. This approach to validation is a bit simple and needs to be better connected to the actual form fields. While it will work for many use cases, in some cases, you might want to wait until explicit "signal forms" support is added to Angular. Tim Deschryver started implementing some abstractions around signal forms, including validation and wrote an article about it. Let's see if something like this will be added to Angular in the future. Why Use Signals in Angular Forms? The adoption of signals in Angular provides a powerful new way to manage form state and reactivity. Signals offer a flexible, declarative approach that can simplify complex form handling by combining the strengths of template-driven forms and reactive forms. Here are some key benefits of using signals in Angular forms: 1. Declarative State Management: Signals allow you to define form fields and computed values declaratively, making your code more predictable and easier to understand. 2. Reactivity: Signals provide reactive updates to form fields, ensuring that changes to the form state trigger reactivity updates automatically. 3. Granular Control: Signals allow you to define form fields at a granular level, enabling fine-grained control over form state and validation. 4. Dynamic Forms: Signals can be used to create dynamic forms with fields that can be added or removed dynamically, providing a flexible way to handle complex form scenarios. 5. Simplicity: Signals can offer a simpler, more concise way to manage form states than traditional reactive forms, making building and maintaining complex forms easier. Conclusion In my previous articles, we explored the powerful features of Angular reactive forms, from dynamic form construction to custom form controls. With the introduction of signals, Angular developers have a new tool that merges the simplicity of template-driven forms with the reactivity of reactive forms. While many use cases warrant Reactive Forms, signals provide a fresh, powerful alternative for managing form state in Angular applications requiring a more straightforward, declarative approach. As Angular continues to evolve, experimenting with these new features will help you build more maintainable, performant applications. Happy coding!...

Oct 4, 2024

5 mins

AngularJavaScript

Making sense of Multiple v-model Bindings in Vue 3

This article is one of a series of articles on what’s new in Vue 3. If you haven’t checked that series yet, you can do so by visiting the links below: - Take your App to the Next Level with Vue 3 - Async Components in Vue 3 - Teleporting in Vue 3 - Your first Vue 3 app using TypeScript - Vue 3 Composition API, do you really need it? In this installment, I will introduce the new v-model in Vue 3 and go through a new feature that allows you to use multiple v-model on the same component! By design, the v-model directive allows us to bind an input value to the state of an app. We use it to create a two-way data binding on the form input, textarea, and select elements. It handles updates in two opposite directions: When the input value changes, it reflects the value onto the state inside the Component. When the Component state changes, it reflects the changes onto the form input elements. The core concept of v-model remains the same in Vue 3 with more enhancements and features. Let’s dig in! Vue 2: v-model Vue 2 supports a single v-model on any given Component. In Vue 2, to build a complex Component that supports two-way data binding, it utilizes a single v-model with one full-blown payload. The Component handles the state internally for all the input elements. It generates a single payload object representing the state of the Component. Finally, it emits an event to the parent Component with the payload attached. This method had several pitfalls, especially for creating Vue UI Libraries. Of these pitfalls is the vagueness of the payload interface. It’s unclear what’s being included in the payload. A developer had to loop through the payload object in order to uncover what properties were there. Another is the need to write the logic inside the Component to handle the internal state and the generation of the payload object. Shortly, we will uncover what has been improved in this regard with Vue 3. However, before this, let’s review some basics on how Vue 2 handles implementing two-way data binding in Components. Vue 2: Two-way Data Binding As mentioned, Vue 2 uses the v-model directive to support two-way data binding on Components. Internally, it follows certain steps and rules in order to support the v-model directive. By default, the v-model directive uses different properties and emits different events for different input elements: Text and Textarea elements use the value property and the input event Checkboxes and Radio buttons use the checked property and the change event Select fields use the input property and the change event. Building a Component with a single input element will internally use something similar to the snippet below: ` The custom Component above defines a single prop named value as follows: ` Then, in the parent Component, you use the new custom Component as follows: ` The v-model directive assumes that the CustomComponent defines an internal property named value and emits a single event named input. What if the CustomComponent has to handle multiple inputs? How do we accomplish that in Vue 2? Well, there is no official solution. However, there are two methods that you can use: The CustomComponent defines a single property named value of type Object. Internally, it parses the object into data fields and does the mapping manually on the template. On every change of any of the fields, it prepares a payload for all the fields and emits a single input event, and attaches the payload. That’s a lot of code to write for such a custom component. The other option is to skip using the v-model directive and instead utilize individual input/event pairs. I will illustrate this in a moment. Assuming you have a custom Component to handle the user’s first name and last name, you would employ something similar: ` As for the properties, the Component defines the following: ` Finally, the parent Component uses the new component as follows: ` We are not using the v-model anymore and providing multiple two-way data bindings on the new component. Further your understanding by reading the official docs on Using v-model on Components Vue 3: v-model In Vue 3, the v-model directive has had an overhaul to give developers more power and flexibility when building custom components that support two-way data binding. The v-model directive now supports new defaults. The default v-model property is renamed to modelValue instead of the old name of value. The default v-model event is renamed to update:modelValue instead of the old name of input. You might be thinking that's more typing when using the new v-model directive. The Vue team are one step ahead and have given you a shorthand to use instead. Let’s rebuild the custom component using it. ` The custom component defines a single prop named modelValue as follows: ` Then, in the parent component, use the new custom component as follows: ` The new v-model directive offers the new shorthand that is used like this: ` The v-model directive assumes that the CustomComponent defines an internal property named modelValue and emits a single event named update:ModelValue. In case you don’t want to use the default naming convention, feel free to use another name. Just remember to be consistent when naming properties. Here’s an example of using a custom name for the modelValue property. ` The custom component above defines a single prop named modelValue as follows: ` Then, in the parent component, you use the new custom component like so: ` Notice the use of the property fullName instead of the default property name. Vue 3: Multiple v-model directive bindings I hope the Vue 3 shorthand form of the v-model directive has given you a "hand up". With this, the v-model gives the flexibility to use multiple v-model directives on a single component instance. The modelValue can be renamed to whatever you want, allowing you to do this! This great new feature eliminates the previous two solutions I offered up on handling complex custom components for Vue 2. Let's jump in and go through an example demonstration! Demo - Multiple v-model directive bindings Let’s build a custom Address component that can be embedded in any form to collect a user’s address. > You can play with the example live on: vue3-multiple-v-model. > You can check the source code for the example on: vue3-multiple-v-model. Figure 1 below shows the final app in action. Let’s start by building the HTML template of the new component. Figure 1 shows that all the fields used are of type input elements. Except for the last one which is a checkbox element. Therefore, it’s suffice to focus on a single input field that will eventually be replicated for the rest of fields. ` The address-line input field binds the :value directive and the @input event as per the new v-model directive specifications in Vue 3. The component defines the following property: ` The other fields follow the same structure and naming convention. Let’s look at the checkbox field and see how it’s defined: ` In the case of a checkbox field element, we bind to the :checked directive instead of the :value directive. Also, we use the @change event instead of the @input event as in the case of input field elements. The event name follows the same standard way of emitting events in the new v-model directive. The component defines the following property: ` Let’s now embed the new custom Address component into the App component: ` For each and every property on the custom component, we bind using the v-model:{property-name} format. The modelValue was replaced with the specific property names we have in hand. When there was a single input binding, the shorthand format was so much easier. However, when there are multiple input elements, the modelValue is in a league of its own! Now, let’s define the properties inside the App component using the new Composition API setup() function: ` You create a new reactive property with an object payload. Finally, you return the reactive property to the component and use it to set bindings on the custom Address component as follows: ` That’s it! Conclusion Vue 3 has many new features and improvements. Today, we saw how we use multiple v-model directives on a single component instance. There is so much more to learn and uncover in Vue 3. The coming installments of this series will continue to look at different features to help you move from Vue 2 to Vue 3. Happy Vueing!...

Nov 6, 2020

6 mins

Vue

Building a Stripe App: A Step-by-Step Guide to QR Code Generation

Building a Stripe App: A Step-by-Step Guide to QR Code Generation Why Build a Stripe App? I recently participated in an audio space with the Stripe team, and something they said really stuck with me: the Stripe app store is a growing area that isn't overly saturated yet. There's a lot of potential for new apps, and companies can use this opportunity to grow. I work at a company called This Dot Labs, and we've created several Stripe apps and even own one. After looking at the data, I can confirm that the Stripe team was right! Creating a QR Code Generator App For this tutorial, we'll build a QR code app that can take a URL and generate a code for it. This is a good use case to help you understand the ins and outs of Stripe's developer tools. Why QR Codes? QR codes are useful tools that have become common in e-commerce, restaurants, and other industries. While Stripe already has a QR code tool, we'll make our own to familiarize ourselves with their syntax and problem-solving approaches. Project Structure Before we dive into the implementation, let's look at the structure of our Stripe App QR Code project: * .vscode: Contains settings for Visual Studio Code * source/views: Holds the main application views * .gitignore: Specifies files to ignore in version control * stripe-app.json: Defines the Stripe app configuration * ui-extensions.d.ts: TypeScript declaration file for UI extensions * .build: this is where the built Stripe app gets placed. Step-by-Step Implementation 1\. Install Stripe Locally First, you need to install Stripe on your local machine. The documentation provides great instructions for this: * For Mac users: Use Brew to install * For Windows users: Download the package and add it to your environment variables You can find the details here in the stripe docs to install the Stripe CLI https://docs.stripe.com/stripe-cli When using Windows, you must do stripe login from Powershell, NOT from Git bash or any other tool. After the server is up, then you can continue using git bash for everything else. After stripe login, you need to enter stripe apps start. Once you do that, the server is up and running and you can go back to using git bash or any other tool. 2\. Install Dependencies We'll be using an extra package for QR code generation. Install it using npm: ` 3\. Set Up the Main Component Let's look at the home.tsx file, where we'll use Stripe's UI components: ` These components are similar to other UI libraries like Bootstrap or Tailwind CSS. 4\. Create the UI Structure Our app will have: * An input field for the URL * Validation using a regex pattern * Error handling for invalid URLs * QR code generation and display Here is the Home.tsx file that is located in the src/views folder ` * ContextView` is at the top level of the app where we see the Title and the link to the Stripe Docs that we placed in our Context View. * Box is how you use Divs. * Banners can be used to show notification errors or any other item you wish to display. * Textfields are input fields. * Everything else is pretty self-explanatory. 5\. Handle Content Security Policy One problem I personally ran into was when I tried to redirect users, the Stripe policies would block it since I did not express that I knew what it was doing. I had to go into the stripe-app.json file and mention the specific security policies. For this particular exercise, I kept these as null. This is my stripe-app.json file. ` 6\. Configure App Views As you can see here, the stripe-app.json file shows the views for each file I have. The Home.tsx file and the Invoice.tsx are also included This is our way of saying that for each view we have, show the app functionality on that page. Our stripe-app.json file will show it but also, the manifest.js file in our .build folder will also show the same. Any view that doesn't have a file will not show the application's functionality. So, if I were to go to transactions, the app would not show the same logic as the home or invoices page. By following these steps, you'll have a fully functional QR code generator app for Stripe. This is just a simple example, but the potential for Stripe apps is massive, especially for businesses serving e-commerce customers. If you need help or get stuck, don't hesitate to reach out, danny.thompson@thisdot.co. The Stripe team is also very active in answering questions, so leverage them as a resource. Happy coding!...

Dec 18, 2024

4 mins

stripe

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Whether it's modernization or custom software solutions, our team of experts can guide you through best practices and how to build scalable, performant software that lasts.

Vue 3 Composition API, do you really need it?

Vue Components / Ways to build them

Component Options API / Traditional method

Component Options API and Mixins

Using the Composition API

Demo

Traditional Vue Components / Options API

Using Mixins in Components

Using Composition API

Conclusion

Bilal Haidar

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Building a Stripe App: A Step-by-Step Guide to QR Code Generation

Let's innovate together!

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Introduction to Zod for Data Validation

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Building a Stripe App: A Step-by-Step Guide to QR Code Generation