ES6 Babel is correctly installed in JavaScript, es6babel

ES6 Babel is correctly installed in JavaScript, es6babel

This document describes how to install Babel6.x ~ First, you can use Babel online conversion https://babeljs.io/repl/

Then go to the topic: Install Babel (command line environment, for Babel6.x)

1. First install babel-cli (used to use babel on the terminal)

Npm install-g babel-cli

2. then install the babel-preset-es2015 plug-in

Npm install -- save babel-preset-es2015

Note: Babel5 contains various conversion plug-ins by default, but Babel6.x related conversion plug-ins need to be downloaded by themselves, such as transform-es2015-arrow-functions, transform-es2015-classes, etc., and ES2015 preset contains all the plug-ins. If no plug-ins are installed, the command line conversion will not work!

The -- save parameter automatically updates the package. json file and writes it to the dependency.

3. Enter the following in the command line:

Babel es6.js -- presets es2015

Output:

　"use strict";　　[1, 2, 3].map(function (x) {　　 return x * x;　　});

Note: The following parameter -- presets es2015 indicates that this plug-in is used for compilation. If you do not write the conversion, it will be ineffective.

4. Plug-in configuration

It is very troublesome to write this parameter every time. You can create a configuration file. babelrc in the current directory.

However, in windows, you cannot right-click a file without a file name. You can use the cmd command line to create a file: Open cmd in the current folder and Type A command

Type nul>. babelrc

You can create a file. babelrc in the current directory, and then write the file:

　{　　　"presets": ['es2015']　} 

Then you can directly use babel es6.js in the command line for conversion without adding parameters indicating the plug-in used

In addition to creating a. babelrc file, you can also configure it in package. json by adding the following attributes:

"babel": {　　"presets": ["es2015"]}

Appendix Common Babel commands:

1. Convert the es6.js file and output it in the program window of the current named row.

Babel es6.js

2. Convert es6.js and output it to the es5.js file (use-o or -- out-file)

Babel es6.js-o es5.js

Babel es6.js -- out-file es5.js

3. Monitor es6.js in real time and re-compile it as soon as it changes (use-w or -- watch)

Babel es6.js-w -- out-file es5.js
Babel es6.js -- watch -- out-file es5.js

4. Compile the entire src folder and output it to the lib folder (use-d or -- out-dir)

Babel src-d lib
Babel src -- out-dir lib

5. Compile the entire src folder and output it to a file.

Babel src -- out-file es5.js

6. directly enter the babel-node command to run ES6 Code directly in the command line.

Babel-node

The above section describes the correct installation process of ES6 Babel in JavaScript. I hope it will be helpful to you. If you have any questions, please leave a message and I will reply to you in a timely manner. Thank you very much for your support for the help House website!