Type Vue without TypeScript

Type Vue without TypeScript

A practical guide for type checking Vue components written in JS and getting things done.

Why do we need types?

In the last decade, browsers have become very powerful, allowing developers to build rich interactive applications. The interactivity and richness have come with an increase in complexity and size of the codebase in the frontend. Large complex codebases demand more attention and frontend teams have become larger.

When more than one developer collaborates, there is a requirement of clear interfaces and APIs. JavaScript is very flexible, but you cannot deduce the type of arguments a function would accept.

e.g., What do you think print function’s argument type is?

function print(value) {

The type of value is ambiguous, even after looking at the source code of the print function which poses problems in large codebases where you cannot afford to jump into the source to deduce argument type of a function. One way to resolve this issue is to document the function’s API, but docs have a tendency of getting outdated.

What if there were a way to know a function’s argument types by just glancing over the function name?

Yes, there is a way: types or TypeScript.

function print(value: string) {

As soon as we look at the print function, we know value should be a string. That little information immediately boosts collaboration and productivity.

In some sense, types make APIs self-documenting. Apart from this, code editors/IDEs also benefit a lot from types. IDEs can provide intelligent suggestions, and display type mismatches inline.

Any application that can be written in J̶a̶v̶a̶S̶c̶r̶i̶p̶t̶ TypeScript, will eventually be written in J̶a̶v̶a̶S̶c̶r̶i̶p̶t̶ TypeScript.> Any application that can be written in J̶a̶v̶a̶S̶c̶r̶i̶p̶t̶ TypeScript, will eventually be written in J̶a̶v̶a̶S̶c̶r̶i̶p̶t̶ TypeScript.#### So TypeScript is it?

TypeScript makes interfaces explicit and enables collaboration, but it comes with its complexity and downsides.

  • Additional time would be spent adding types.
  • JavaScript’s flexibility is lost as we have to type everything and sometimes it gets very complicated to add types.
  • A steep learning curve and retraining of developer staff.

Vue and TypeScript

Vue provides a fluent object-based API for authoring composable components.


export default {
  data() {
    return {
      items: []
  methods: {
    add(text) {
      this.items.push({ text, done: false })
    complete(index) {
      this.items[index].done = true

The above component can be written in TypeScript as:


import { Component, Vue } from 'vue-property-decorator';

interface TodoItem {
  text: string
  done: boolean

export default class Todo extends Vue {
  private items!: TodoItem[]

  private add(text: string) {
    this.items.push({ text, done: false })

  private complete(index: number) {
    this.items[index].done = true

With TypeScript, you get type based intellisense which boosts developer productivity.

TypeScript support in Vue was an afterthought, and it becomes quite verbose in real-world applications. Good thing is that’s going to change with Vue 3 coming mid-next year.

Adding types to Vuex is even more complex and unpleasant. Also, the intellisense on state/getter/actions mapped to components is almost non-existent.

Any application that can be written in J̶a̶v̶a̶S̶c̶r̶i̶p̶t̶ TypeScript, will eventually be written in J̶a̶v̶a̶S̶c̶r̶i̶p̶t̶ TypeScript.> Any application that can be written in J̶a̶v̶a̶S̶c̶r̶i̶p̶t̶ TypeScript, will eventually be written in J̶a̶v̶a̶S̶c̶r̶i̶p̶t̶ TypeScript.
Yes, that’s true, and tools like ESLint are far more helpful in catching these bugs.

So, do we need TypeScript at all?

Maybe but you don’t need to jump on it today. TypeScript ensures type safety, documents API interfaces and enables intellisense in IDEs. I feel intellisense is far more critical in Vue application projects than type safety.

The best thing about TypeScript is that you can take advantage of TypeScript without using TypeScript.

Yes, with VS Code and TypeScript, we can get intellisense in JavaScript files. We can enforce type safety too if we want that. VS Code infers JSDoc annotations to generate TypeScript definition on the fly. Let’s set up a JavaScript project with types and intellisense.

Intellisense in JavaScript

In JavaScript files, VS Code infers types for static values to provide intellisense, including object property names, function return value type, and property types.

VS Code has automatic type acquisition which uses npm package’s bundled types or community types from DefinitelyTyped to provide intellisense, including method signature and parameter info. Also, using Vue’s type information and Vetur plugin, it can provide rich completions and type information in .vue files too.

However, static type inference for array literals and dynamic values is not possible, for such cases, VS Code can use JSDoc annotations to collect type information. In the following snippet, type of this.items is detected as an array of type any, as it’s known statically that this.items is an array, but there is no information about values in the array. We can use a@type annotation for adding type information to this.items, @type allows adding type information, similar to any typed language (or TypeScript).

VS Code type inference from JSDoc comments is as reasonable as TypeScript. See the following code snippets written in JavaScript and TypeScript.

Using JSDoc to add type information to Vue components

Vue component options have data, props, computed and methods which when provided with type information can significantly improve the developer experience.

1\. Data

We have to provide @type annotations for properties which are impossible infer statically. e.g.:

In the above snippet, items and currentItem have incomplete type information, so we need@type annotations only for those two properties.

Type definitions for items and currentItem are quite similar. If we were writing TypeScript, we would have created an interface for the item type. With JSDoc, we can define custom types or interfaces using a@typedef annotation.

Autocomplete suggestions and type information for data are available on this context in life-cycle hooks, methods, computed and watch handlers.

2. Props

For primitive props, VS Code can infer type information automatically.

However, if you have Object or Array as the type, then auto-inferred type information is useless. In such cases, we have to provide type information with a @type annotation.

It even works with the validator options syntax for props.

When defining prop names as an array, it’s a little complex to provide type information. It is discouraged to use names array for props definition.

3. Computed

For computed properties, automatic return type inference does not work as expected but it does provide computed property names in suggestions.

So with a @returns annotation, we can provide type information for the returned value as well.

4. Methods

Method names are available in VS Code suggestions on this context, but they lack type information.

Here, we see the add method accepts one parameter text and returns a number, the auto inferred information is already beneficial, and if we can provide type information for the text parameter, we get the complete experience of a typed language. Moreover, we can add types to parameters using the @param annotation.

We can even provide a small description of the method if it’s not clear from its name.

VS Code supports even more JSDoc annotations; you can find the complete list of supported annotations on the VS Code wiki page.

Can we do strict type checks in JavaScript?

Yes, it’s possible, add // @ts-check at the start of the script in .vue file.

If you want to enable strict type checks in the whole project, then you should add a jsconfig.json file to the project root.

  "compilerOptions": {
    "checkJs": true

You can find more options at the [jsconfig.json]([https://code.visualstudio.com/docs/languages/jsconfig)](https://code.visualstudio.com/docs/languages/jsconfig) "https://code.visualstudio.com/docs/languages/jsconfig)") reference.

Learn more

Learn Web Development Using VueJS

Learn by Doing: Vue JS 2.0 the Right Way

Vue.js 2 Essentials: Build Your First Vue App

Getting started with Vuejs for development

Horizontal Feed Component with Sass and VueJs 2

What are the differences between the various JavaScript frameworks? E.g. Vue.js, Angular.js, React.js

What are the differences? Do they each have specific use contexts?

What are the differences? Do they each have specific use contexts?

Ember.js vs Vue.js - Which is JavaScript Framework Works Better for You

Ember.js vs Vue.js - Which is JavaScript Framework Works Better for You

In this article we will discuss full details and comparison of both Ember.js and Vue.js

JavaScript was initially created to work for web applications. But today they have become the favorite of mobile app developers. Most of the developers prefer to work with frameworks based on JavaScript. It simplifies coding. You can use JavaScript with almost any framework.

The use of a particular framework will decide how easy and fast it is to create the app. So, you must choose the best one suited for the app that you are planning to build. You must make a wise choice so that you benefit in the end. Among the crowded market, two of the frameworks stand out. We will make a comparison between Ember.js and Vue.js.

Why Do You Select A Particular Framework?

Before we start comparing the two frameworks, we should understand the factors that lead to the choice of a framework. Each developer chooses a framework before he or she goes to work on an app. Let us see the reasons for the selection.

● The codes must be easy to understand and transparent.

● The framework should give the maximum power with the least amount of coding.

● The framework should provide a well laid out structure to work on.

● Does the framework support an in-built router or an external plug-in router?

● The framework should be able to transfer more data on a full page-load so that it becomes a single-page app. A single-page app is more beneficial for the application.

● In single page architectures if there is a need for users to share links to sub-screens within the interface, then the framework should have the capacity to route based on the URL.

● A tighter template option can help in enabling two-way binding.

● The framework should not conflict any third-party library.

● Testing the codes inside the framework should be easy.

● The framework should provide the HTTP client service for AJAX calls

● The documentation is essential. It should be complete and up-to-date.

● The framework should be compatible with the latest version of the browser.

● The framework has to fulfill the above conditions for easy construction of the app. You must ensure that the framework you choose meets the conditions.

Vue.js Explained

Developers are always looking at new frameworks to build their apps. The main requirements are speed and low cost. The framework should be easy to use by even new developers. You should be able to use it at low cost. Other considerations are about simple coding, proper documentation, etc.

Vue.js combines a lot of good when it comes to software language for web app development. The architecture of Vue.js is easy to put in use. The apps developed using Vue.js are easy to integrate with new apps.

Vue.js is a very lightweight framework. It makes it fast to download. It is also much faster than other frameworks. The single-file component nature of the framework is also beneficial. The size has made it very popular.

You can further decrease weight. With Vue.js you can separate the template-to-virtual DOM and compiler. You can only deploy the minified and zipped interpreter which is only 12 KB. You can compile the templates in your machine.

Another significant advantage of Vue.js is that it can integrate easily with existing applications created with JavaScript. It will make it easy for using this framework to make changes to applications already present.

Vue.js also integrates easily with other front-end libraries. You can plug in another library and make up for any deficiency in this framework. This feature makes this tool a versatile one.

Vue.js uses the method of rendering on the streaming-side server. You can render your component and get a readable stream. You can then send this to the HTTP server. It makes the server highly responsive. Your users will get the rendered content very quickly.

Vue.js is very SEO friendly. As the framework supports server-side rendering, the views are rendered directly on the server. The search engines list these.

But the most important thing for you is the ease with which you can learn Vue.js. The structure is elementary. Even new developers will find it easy to use it to build their apps. This framework helps in developing both small and large templates. It helps to save a lot of time.

You can go back and check your errors very easily. You can travel back and inspect all the states apart from testing your components. It is another important feature as far as any developer is concerned.

Vue.js also has very detailed documentation. It helps in writing your applications very quickly. You can build a web page or app with the basic knowledge of HTML or JavaScript.

● Vue.js has pure architecture. It helps in integration with other apps

● Vue.js is lightweight and fast. It can be made lighter by deploying only the interpreter

● You can separate the compiler and the template-to-virtual DOM.

● Due to smooth integration, you can use this to make changes to existing apps

● To make up for any shortfall, you can plug-in any library and makeup.

● As Vue.js uses streaming-side server rendering, your users can get quick responses.

● The server-side rendering also helps in being ranked higher by search engines.

● It has a simple structure. Easy to use for any new developer

● You can go back and check and correct your errors.

● You can check all the existing states.

● Detail documentation also helps build the web page or application very quickly.

Ember.js Decoded

Ember.js is an MVVM model framework. It is open-source software. This platform is mostly used for creating complex multi-page applications. It maintains up-to-date features without discarding any of the old features.

With this framework, you have to follow the architecture of the framework strictly. The JS framework is very tightly organized. It reduces the flexibility that other frameworks might offer.

There is a very refined and developed control system for its platforms and tools. You can integrate it with the new version with the tools provided. There is strict guidance about avoiding outdated APIs.

You can understand Ember’s APIs easily. They are also easy to work. You can make use of highly complex functionalities simply and straightforwardly.

The performance is better as similar jobs are processed together. It creates batches of similar bindings and DOM updates to improve the performance. It means that the browser needs to process them in one go. It will avoid recomputing for each task, wasting a lot of time.

You can write the codes in a simple manner and modules. You can use any of Ember’s APIs. It is possible due to the presence of Promises everywhere.

Ember comes with a well-written guide. The API is recorded in a useful manner. It is a front-end framework that is loaded. Ember has a router, pipeline, services, etc. of its own.

The basis for views, controllers, models, and framework is the Ember Object Model. All components come from the same objects. The framework is firm and steady. The reason is that all elements have similar jobs and characteristics.

Ember has made the general application, organization, and structure clear so that you don’t make any mistakes. You will have no chance to complicate the application unnecessarily. If you have to go out of the defined limits, you will have to force your way out.

The language used for templating in Embers is Handlebars. This language helps Embers to keep its logic out of view. The clean syntax of Handlebars makes it easy for you to read and understand the templates. Handlebar templates are faster to load.

Another advantage you gain from Handlebar is that you don’t have to update your template every time you add or remove data from the page. It will be done automatically by the language itself.

A community that is continually improving the framework supports Ember. They are updating the framework with the latest technology. They also make sure that backward compatibility is possible.

● Ember.js is an open-source MVVM model framework suitable for complex multiple-page applications.

● It offers both the latest and old features.

● It has a very tightly structured framework which doesn’t offer much flexibility

● A very refined control system helps you to integrate with new versions without any problem.

● There is strict guidance about avoiding outdated API versions.

● Ember’s APIs help you to use complex functionalities in a simple manner

● There is no recomputing for each task as the framework allows the browser to do similar functions together.

● Promises allow you to write modular and straightforward code using any API of Ember.js.

● Ember.js is a fully loaded, front-end framework.

● The framework is stable because all components have the same functionalities and properties.

● It has well-defined limitations which will prevent your complicating your application

● Handlebars, the language used by Ember.js allows you to read and understand templates easily. It also helps to load the templates faster.

● Handlebars will ensure to update the template every time you add or remove data.

● Ember.js has an active community that updates the framework regularly and facilitates backward compatibility.

A Comparison Between Ember.js And Vue.js

This article intends to compare the features of both frameworks. Let us see how the characteristics of these frameworks compare. It will help you to make use of the right framework for your web application.

When you need a modern engine for an old application, it is Vue.js which will help you. It combines the best properties of other frameworks. Vue.js is a developing framework. A ready-to-use library of interface elements does not exist. However, many third-party libraries can help you.

Ember.js offers you a well-organized and trustworthy framework. When the development team is big, this is the framework that suits best. It allows everyone to understand the written code and contribute to a common project. The technology will be up-to-date, and the platform will be stable.

Vue.js can help you use the syntax of different kinds. It helps in writing the codes with ease. It is also an SEO friendly framework. Ember is a fully loaded front-end framework and can help you develop the applications very fast. But it is not suitable for developing small projects.

It is not easy to say this is better than that. It will depend on what kind of project you have undertaken. Both have their pluses and minuses. The below table will help in a better comparison.

Final Thoughts

It is not easy to conclude as to which is better. It all depends on the application that you want to develop. Both frameworks are developing. Both are getting updates. Both the communities are working on the frameworks.

While Vue.js is more comfortable for writing codes, Ember is a full-stack framework allowing the development of apps very fast. It is suitable for big projects. It is too complicated to be used for smaller projects.

We hope you had a great time reading this article. If you’ve any questions or suggestions related to this blog, then feel free to ask them in the comment section. Thank You.!