Shulou(Shulou.com)06/02 Report--

This article mainly explains "what are the reasons for using TypeScript". Friends who are interested might as well take a look. The method introduced in this paper is simple, fast and practical. Now let the editor take you to learn "what are the reasons for using TypeScript?"

TypeScript reduces the risk of code errors

It's natural for developers to write BUG. Almost half the time, we are looking for the cause of the program error. In JavaScript, the reason may be as simple as a type error. For example, assigning a numeric value to a string variable is fine in JavaScript, but compilation fails in TypeScript. JavaScript developers have been plagued by this problem for a long time and have even introduced strict patterns (Strict mode) to reduce such errors.

Const getLength = (someString: string) = > someString! = undefined? SomeString.length: 0; let testTS = "what"; testTS = 3000; / / Type'"what"'is not assignable to type 'string' getLength (testTS)

With TypeScript, the above code cannot be compiled and will not appear in the final code base. Using JavaScript is not the case. Even if TypeScript cannot avoid runtime type errors, it can still effectively reduce this risk.

Principle of quick failure

Before the code works properly, TypeScript introduces a new mandatory step: converting the code to JavaScript. This step may also fail many times a day when writing new code. Languages that are not statically typed defer failure and error detection to run time. Nullable types are important for any modern language, and they help to extend the code.

Adrian Colyer wrote a very interesting article in 2017: quantifying detectable errors in JavaScript. At the end of the article, you can find an interesting experimental result. Eric surveyed 400 BUG exposed in the JavaScript project, and 59 of them can be effectively captured by using TypeScript or Flow without appearing in a production environment. Note that in this article, we are only thinking about reducing error codes.

Make the code richer in information / documentation

Today, writing reusable code and reusable components is fun in front-end development. Rebuilding the wheel is error-prone and expensive. Therefore, it is best to use existing libraries or code. TypeScript adds a lot of information to the code and enforces this usage. The output TypeScript code contains more relevant information, such as type signatures, and so on. On the other hand, the explanatory information of the JavaScript code is very little, so it is more difficult to read. You need to provide information either in the form of JSDoc or in the form of some external document. When a large amount of code is reused, the development efficiency is reduced.

Of course, it's still important to read and document, but type hints make the code more readable. This is especially true for people who do not yet fully understand your code base. IntelliSense is more suitable for Typescript because it can obtain type signature information.

In the short term, using TypeScript sometimes does mean typing more words. In addition, because TypeScript will be converted to JavaScript and mixed with the JavaScript code base, you do need to fight it sometimes and shut it down in some places. But in the long run, TypeScript can be extended, while JavaScript is difficult to expand. Using TypeScript now can help your developers in the future.

TypeScript has more functions than JavaScript

TypeScript has more functions than JavaScript. Obviously, static type checking is the most important one, but there are others. Most of the features of TypeScript (previously not implemented by JavaScript) are now implemented in JavaScript. But TypeScript still has an advantage because it evolves faster than JavaScript. Such as interfaces, namespaces, generics, abstract classes, data modifiers, optional, function overloading, decorators, utils types, and readonly keywords. This article is not intended to cover all of these features, but simply give a read-only TypeScript util

Interface Article {title: String; content: String;} / * Pure function, that translates the article and returns it * / const translate = (article: Readonly) = > {const article2 = {... article}; article2.title = translateText (article.title); / / Cannot assign to 'content' because it is a read-only property artilce.content = translateText (article.content); / / Ooops, developer meant articles.content =. Return article2}

Better refactoring and tools

Refactoring TypeScript code is much easier than using an untyped language. I've seen many JavaScript developers use global searches and substitutes to rename variables, resulting in unit tests failing. With TypeScript, you can get additional semantics in your code. When using an interface or class, the compiler knows which fields the object will contain. Renaming fields for interfaces, classes, or enumerations is now easier than ever. You can witness miracles simply by using the refactoring capabilities of VSCode or IntelliJ.

Strong background

A widely used technology has almost unlimited resources to learn it. This is the case with TypeScript because it has a large community.

If you are considering using Angular, you have no choice but to choose TypeScript. Starting with Angular 2, Google has completely adopted TypeScript as its main language. If you do not use Angular, but use React with TypeScript, it will greatly reduce the complexity of developing Angular projects in the future.

An alternative to solving the problem of static types in JavaScript

One of the problems with JavaScript for a long time has been that there are no static types. In the past, this problem has plagued developers, but the project still has to go ahead. In the development of JavaScript, we have been trying to add static types.

For example, React released PropTypes for its components to reduce type errors during the development phase-- a feature fully covered by TypeScript. Facebook also has its own static type checking library (Flow), which is basically the same principle as TypeScript. In 2014, Google also introduced a JavaScript-based scripting language that extends TypeScript, called AtScript.

Other advantages of TypeScript

TypeScript is written and maintained by Microsoft. This is a project that the tech giants have taken the time to carefully maintain to make the language more sense of security-like.

Not only is TypeScript completely open source under the MIT license, but the project also provides a transparent roadmap and the ability to submit feature requests.

The TypeScript compiler is written entirely in TypeScript, so once you have confidence in the language, you can even contribute to the code base and extend its functionality!

At this point, I believe you have a deeper understanding of "what are the reasons for using TypeScript?" you might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.