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!