What is the difference between javascript and typescript

Difference: 1. The data in TypeScript requires a clear type, but JavaScript does not. 2. TypeScript introduces the concept of "class" that is not found in JavaScript. 3. TypeScript provides compile-time static type checking through type annotations.

The operating environment of this tutorial: windows7 system, ECMAScript 5&&typescript3 version, Dell G3 computer.

TypeScript and JavaScript are two of the more popular scripting languages ​​​​in current project development. We already know that TypeScript is a superset of JavaScript, but what is the difference between TypeScript and JavaScript? When choosing a development language, how should you choose?

This article will compare these two languages ​​in depth, discuss the connections and differences between the two languages, and outline the advantages of each.

Overview of JavaScript and TypeScript

JavaScript

JavaScript is a lightweight The interpretive scripting language 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.

JavaScript is object- and event-driven and does not require a specific language environment. It only needs to run on supported browsers.

The JavaScript language has the following characteristics:

• JavaScript is a scripting language that does not require compilation. As long as it is embedded in the HTML code, it can be loaded and interpreted line by line by the browser. implement.

• JavaScript is an object-based language that allows you to create objects while using existing objects. But Javascript does not support inheritance and overloading functions that other object-oriented languages ​​have.

• JavaScript has a simple syntax and uses weakly typed variables.

• JavaScript language is relatively safe and is only executed on the browser side and will not access local hard disk data.

• The JavaScript language is dynamic. JavaScript is event-driven and only responds to user actions.

• JavaScript only depends on the browser and has nothing to do with operating system factors. Therefore JavaScript is a cross-platform language.

• JavaScript has good compatibility and can be used with other technologies (such as XML, REST API, etc.).

Related recommendations: "JavaScript Video Tutorial"

TypeScript

TypeScript is developed by Microsoft and An object-oriented programming language maintained. It is a superset of JavaScript, contains all elements of JavaScript, can load JavaScript code to run, and extends the syntax of JavaScript.

TypeScript has the following characteristics:

• TypeScript is an open source language launched by Microsoft, using the Apache license agreement

• TypeScript has added Static types, classes, modules, interfaces and type annotations

• TypeScript can be used to develop large-scale applications

• TypeScript is easy to learn and understand

Main Differences between JavaScript and TypeScript

TypeScript can use all code and coding concepts in JavaScript, TypeScript is designed to make JavaScript Created to make development easier. For example, TypeScript uses concepts such as types and interfaces to describe the data being used, which enables developers to quickly detect errors and debug applications

• TypeScript models from core language aspects and class concepts Extend the JavaScript object model in terms of plasticity.

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

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

• Data in TypeScript requires explicit types, but JavaScript does not.

• TypeScript provides default parameter values ​​for functions.

• TypeScript introduces the concept of "classes" that are not found in JavaScript.

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

Advantages of TypeScript

The following are the significant advantages of TypeScript compared to JavaScript:

1. Static typing

Static typing is a feature that detects errors while developers are writing scripts. Finding and fixing bugs is a critical need for today's development teams. This feature allows developers to write more robust code and maintain it, resulting in better code quality and clarity.

2. Large Development Projects

Sometimes small incremental changes to the code base are needed to improve a development project. These small changes can have serious, unintended consequences, making it necessary to undo them. Using TypeScript tools to make refactoring changes is easy and fast.

3. Better collaboration

When developing large projects, there will be many developers, and the chances of garbled code and errors will also increase. Type safety is a feature that detects errors during coding, rather than when compiling the project. This creates a more efficient coding and debugging process for development teams.

4. Greater Productivity

Factors such as clean ECMAScript 6 code, auto-completion and dynamic input help improve developer productivity. These features also help the compiler create optimized code.

Advantages of JavaScript

Compared to TypeScript, JavaScript also has some obvious advantages.

1. Popularity

The JavaScript developer community is still huge and active, and you can easily find a large number of mature development projects and available resources in the community.

2. Learning curve

Because the JavaScript language developed earlier and is more mature, there are still a large number of developers who insist on using their familiar scripting language JavaScript instead of learning TypeScript.

3. Native 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

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.

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