What are the differences between javascript and typescript?

Javascript and typescript are both scripting languages ​​used for development, so what are the differences between javascript and typescript? The next article will introduce to you the difference between javascript and typescript. Friends who are interested can take a look.

Without further ado, let’s go straight to the text~

What are the differences between javascript and typescript?

The difference between javascript and typescript 1: Concept comparison

JavaScript is a lightweight interpreted scripting language that does not require Compiled, can be embedded into HTML pages and executed on the browser side, which can realize rich interactive functions on the browser side and bring users a smooth and diverse user experience.

TypeScript code is saved in the ts file. After the ts file is compiled, a js file will be generated. Any valid JavaScript code can be directly compiled as TypeScript code, but the compiled code is the same as the original JavaScript code. After TypeScript code is compiled, it will be converted into the corresponding JavaScript code.

The difference between javascript and typescript 2: Content comparison

1. TypeScript introduces the concept of "class" that is not found in JavaScript.

Although ES6 already supports classes, TypeScript and ES6 classes are still not exactly the same. ts code can declare the type of variables through type annotations.

2. Data in TypeScript requires a clear type, but JavaScript does not.

3. TypeScript provides compile-time static type checking through type annotations.

let str: string;//ts代码
let str;//编译生成的js代码

It can be clearly seen through comparison that in ts code, ": type" can be added when declaring a variable to describe the type of the variable, that is, type annotation.

4. TypeScript extends the JavaScript object model from the core language aspects and the modeling of class concepts.

5. JavaScript code can work with TypeScript without any modification, and a compiler can be used to convert TypeScript code into JavaScript.

6. TypeScript provides default parameter values ​​for functions.

In TypeScript functions, we can provide type annotations for each parameter and return type annotations (":type" after the parameter list) for the function. At the same time, TypeScript can add one? Represents optional parameters.

7. TypeScript introduces the concept of modules, which can encapsulate declarations, data, functions and classes in modules.

The difference between javascript and typescript 3: Comparison of advantages

Advantages of javascript:

1. Popularity: JavaScript The developer community is still huge and active, and a large number of mature development projects and available resources can be easily found in the community.

2. Learning curve: Since the JavaScript language developed earlier and is relatively mature, there are still a large number of developers who insist on using their familiar scripting language JavaScript instead of learning TypeScript.

3. Local browser support: TypeScript code needs to be compiled (output JavaScript code), which is an extra step when TypeScript code is executed.

4. No comments required: In order to take full advantage of TypeScript features, developers need to constantly comment their code, which may make the project less efficient.

5. Flexibility: Some developers prefer the flexibility of JavaScript.

Advantages of typescript:

1. It is convenient for developers to make comments.

2. It can help developers detect errors and modify them.

3. TypeScript tools make refactoring changes easy and fast.

4. TypeScript introduces the concept of "class" that is not found in JavaScript.

5. TypeScript introduces the concept of modules, which can encapsulate declarations, data, functions and classes in modules.

6. Type safety features can detect errors during coding, which creates a more efficient coding and debugging process for developers.

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