How TypeScript Makes You a Better JavaScript Developer

Key advantages of TypeScript:

• Enhance developer confidence: TypeScript significantly enhances JavaScript developers' confidence by catching errors before code runs, simplifying code refactoring, reducing unit testing needs, and improving editor coding experience.
• Improving code readability and predictability: TypeScript's type system makes code easier to understand and predict its behavior, thus reducing the risk of errors and supporting "continuous refactoring".
• Reduce unit tests: TypeScript can catch type mismatch errors during development without writing certain unit tests (such as function signature tests), allowing developers to focus on more complex tasks.
• Strong IDE support: Both the main IDE and editor support TypeScript, which increases productivity by automating and writing "future" JavaScript. TypeScript's compatibility with modern JavaScript frameworks and libraries further extends its usefulness.

Companies such as Airbnb, Google, Lyft and Asana have moved multiple codebases to TypeScript.

Just like we pursue a healthy diet, exercise and adequate sleep, programmers are eager to improve their skills. This article will provide you with practical advice on improving your JavaScript development skills.

What is TypeScript?

TypeScript is a compiled language that compiles into JavaScript. Essentially, you're writing JavaScript, but with a type system. For JavaScript developers, migration is very smooth because the two languages ​​are almost the same except for a few nuances.

The following is a simple JavaScript and TypeScript function example:

<code class="language-javascript">function helloFromSitePoint(name) {
    return `Hello, ${name} from SitePoint!`
}</code>

<code class="language-typescript">function helloFromSitePoint(name: string) {
    return `Hello, ${name} from SitePoint!`
}</code>

The difference between the two is the type annotation of the "name" parameter in TypeScript. This tells the compiler: "Make sure that when this function is called, only strings are passed in." This example shows only the basic functionality of TypeScript.

How does TypeScript improve your skills?

TypeScript improves your JavaScript development skills by:

• Benefit your confidence: Benefit your confidence when dealing with unfamiliar codebases and large team projects.
• Reduce production environment errors: Catch potential production environment errors at compile time, not at runtime.
• Simplify code refactoring: TypeScript catches errors when you refactor your code, making the refactoring process easier.
• Reduce unit tests: Reduce the need for certain unit tests (such as function signature testing).
• Enhance the editor coding experience: Provides better code completion and "future" JavaScript support.

Let us explore these aspects more deeply.

Enhance confidence

TypeScript improves your confidence in unfamiliar with codebases and large teams. If you are familiar with TypeScript, you will feel more at ease when joining a new team or project using TypeScript. TypeScript provides higher code readability and predictability, allowing you to infer how your code works immediately. This is the direct benefit of the type system.

Function parameters are annotated, so TypeScript knows the valid type of the value you are passing.

<code class="language-javascript">function helloFromSitePoint(name) {
    return `Hello, ${name} from SitePoint!`
}</code>

Function return type will be inferred or annotated.

<code class="language-typescript">function helloFromSitePoint(name: string) {
    return `Hello, ${name} from SitePoint!`
}</code>

In TypeScript, team members' code is usually self-explanatory. They don't need to explain the code because the type adds context to the code. These features allow you to trust your team more. You can focus on higher-level tasks because you don't have to spend time worrying about low-level errors. The same applies to your code. TypeScript forces you to write explicit code, which directly improves the quality of your code. Ultimately, you will find yourself more confident in JavaScript development using TypeScript.

Reduce production environment errors

TypeScript catches potential production environment errors at compile time rather than runtime. When you write your code, TypeScript will warn you if an error occurs. For example, see the following example:

Note the red wavy line below the colors variable? This is because we are calling the .forEach method, but it may not be defined. This may cause production environment errors. Fortunately, TypeScript warns us when we write our code and won't compile until we fix the error. As a developer, you should catch such errors before the user. TypeScript almost always eliminates these types of errors, because you can see them when your code is compiled.

Simplified code refactoring

With TypeScript, code refactoring becomes easier because it catches errors for you. If you rename a function, it will tell you if you forget to use the new name somewhere. TypeScript corrects you when you change the shape of an interface or type and delete attributes that you think are not used. Any changes you make to your code, TypeScript will remind you behind you: "Hey, you forgot to change the name on line 142." Some people call this "continuous refactoring" because you can quickly refactor your codebase's Most of the content. This is a great feature and ensures future maintainability.

Reduce unit tests

TypeScript eliminates the need for certain unit tests, such as function signature testing. For example, the following function:

<code class="language-typescript">type Color = "red" | "blue" | "green"

// 此处，您知道 color 必须是 "Color" 类型，即三个选项之一
function printColor(color: Color) {
  console.log(`The color you chose was: ${color}`)
}</code>

We no longer need unit testing to ensure that we call getAge with the appropriate type of value. If the developer tries to call getAge with number, TypeScript throws an error telling us that the type does not match. So this allows us to reduce the time we write simple unit tests and spend more time writing code we prefer.

Improve the editor coding experience

One of the most beneficial aspects of TypeScript is to increase productivity through autocomplete and “future” JavaScript. Most major IDEs and editors, including Atom, Emacs, Vim, VSCode, Sublime Text, and Webstorm, have TypeScript tool plug-ins. This section will introduce some features in VSCode.

The first feature to increase your productivity is automatic completion. When you look for a method or property on a class or object, it can automatically complete the name for you if TypeScript knows its shape. Here is an example:

Note that I have not completed the input of the myFriend property. Here you can see TypeScript starts suggesting property names because it knows the shape matches User.

I am writing a function called printUser . I want to record the user's full name to the console. I go to define lastName and see a red wavy line. Hover over my editor and TypeScript tells me: "The property 'lastName' does not exist on type 'User'." This is very useful! It helped me catch my low-level error. Very good, right?

The second feature that improves our experience is TypeScript's ability to write "future" JavaScript. Usually, we need multiple Babel plugins to do this. TypeScript, on the other hand, provides the same functionality, but only requires one dependency. The TypeScript team did a great job following the ECMAScript specification, adding the language features of Phase 3 and above. This means you can take advantage of new JavaScript additions without having to deal with too many dependencies or configurations. Doing so will put you ahead of other JavaScript peers. Combining these two features will increase your efficiency as a JavaScript developer.

How to start learning TypeScript?

If you are interested in starting TypeScript, you can choose the following ways according to your learning method:

• TypeScript Five-minute Getting Started: The Quick Start Guide for TypeScript Manual will provide you with practical experience in the language. It will guide you through the basic functions of the language. You only need five minutes, an editor and the willingness to learn to start.
• TypeScript Getting Started Guide: If you want to go a step further, we recommend this article, which will cover some basic concepts and help you run TypeScript locally.
• Programming TypeScript by Boris Cherny: For those who like to learn deeply—we refer to learning deeply—see this O’Reilly book by Boris Cherny. It covers content from basic to high-level language features. If you want to take your JavaScript skills to the next level, we highly recommend this book.

Try it!

It is important to listen to others' opinions, but nothing is more important than forming one's own perspective based on experience. We know TypeScript will enhance your confidence, help you catch errors and refactor code faster, and increase your overall productivity. Go and try TypeScript now and let us know what you think!

More TypeScript articles are coming soon!

If you liked this post, you'll be happy to hear that we have more articles about TypeScript coming soon. Please follow us in the next few months. We will cover some topics such as getting started with TypeScript and using it in conjunction with technologies like React. Before that, I wish you a happy coding!

Frequently Asked Questions (FAQ) about TypeScript and JavaScript Development

What is the main difference between TypeScript and JavaScript?

TypeScript is a superset of JavaScript, which means it contains all the features of JavaScript and some other features. The main difference between the two is that TypeScript contains a type system. This means you can use its type to annotate variables, functions, and properties. This feature makes TypeScript more robust and easier to debug because it catches errors at compile time rather than runtime. JavaScript, on the other hand, is dynamically typed and does not have this feature.

How does TypeScript improve JavaScript development?

TypeScript enhances JavaScript development in a variety of ways. It provides static typing that can catch potential errors before the code runs. It also provides better tools including automatic completion, type checking, and advanced refactoring, which can significantly increase developer productivity. TypeScript also supports the latest JavaScript features and provides the option to compile your code into a version of JavaScript that can run on all browsers.

Is it difficult to migrate from JavaScript to TypeScript?

Migrating from JavaScript to TypeScript is usually simple, especially for developers who are already familiar with statically typed languages. TypeScript is a superset of JavaScript, so valid JavaScript code is also valid TypeScript code. The main learning curve comes from understanding and efficiently utilizing TypeScript.

Can TypeScript be used for large projects?

Yes, TypeScript is especially suitable for large projects. Its static typing and powerful tools make it easier to manage and navigate large code bases. TypeScript's capabilities can help catch errors in development as early as possible, which is critical for large projects with many moving parts.

What is the career prospect of TypeScript developers?

The demand for TypeScript developers is growing as more companies recognize the benefits of using TypeScript for large-scale application development. TypeScript developers can work in a variety of roles, including front-end developers, back-end developers, full-stack developers, and software engineers. They can also work in a wide range of industries, from tech startups to large companies.

How does TypeScript integrate with modern JavaScript frameworks?

TypeScript integrates well with modern JavaScript frameworks such as React, Angular, and Vue. These frameworks provide TypeScript definitions, which means you can write components using TypeScript and benefit from features like their static typing and better tools.

What impact will use TypeScript have on performance?

TypeScript is a compile-time language, which means it is converted to JavaScript before it runs in the browser. Therefore, the performance of TypeScript applications is basically the same as that of JavaScript applications. The main performance cost comes from the compilation process, but this is usually negligible and can be optimized with appropriate tools.

How does TypeScript handle asynchronous programming?

TypeScript Like modern JavaScript, it supports asynchronous programming using Promises and async/await syntax. This makes it easier to write and manage asynchronous code, which is often necessary for tasks such as network requests.

Can I use JavaScript libraries in TypeScript?

Yes, you can use the JavaScript library in TypeScript. Most popular JavaScript libraries provide TypeScript definition files that provide type information for the library's functions and objects. This allows you to use these libraries while still benefiting from TypeScript's type checking and autocomplete.

Is TypeScript suitable for beginners?

Although TypeScript's learning curve is steeper than JavaScript due to its static type, it is still suitable for beginners. The additional structure and tools provided by TypeScript can actually make it easier to learn programming concepts and debug code. However, before learning TypeScript, it is best to learn the basics of JavaScript first.

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