Develop React in emacs in rjsx-mode

投稿日：2017年9月3日更新日：2017年9月5日

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Abstract

Hello everyone this is candle.
In this time I would like to introduce rjsx-mode of major-mode for react development of emacs.

The development of “react” has been tried and errored between emacs users, such as using web-mode or js2-jsx-mode of js2-mode.
Also I had been used js2-jsx-mode before rjsx-mode.

Since rjsx-mode is an extension of js2-mode, users of js2-mode can use it without discomfort.
rjsx-mode has auto complete function of jsx. it’s fantastic.

Precondition

You use emacs
You use melpa or el-get

Installing rjsx-mode

You can install rjsx-mode from melpa or el-get.
I am using el-get, but I will explain both easily.

install with mepla

Lauch emacs and run ” M-x package-list-packages”

Emacs will display the melpa package index. You would search “rjsx-mode” with C-s

Move the cursor to rjsx-mode, type “i”, then type “x” to install.
You are asked whether you want to install it, you can install it by typing “y”.

Installation with melpa is over.

Install with el-get

It is easy to install rjsx-mode with el-get.
At first, you open the emacs conf file. I will open ~/.emacs.d/init.el file

write it.

(el-get-bundle rjsx-mode)

Reload init.el with “M-x eval-buffer and install rjsx-mode from el-get.

You can see that js2-mode is installed if you are looking at the progress.

It’s over.

rjsx-mode configuration

rjsx-mode automatically starts up in major mode for .jsx extension.
On the other hand, since it is not bind with .js extension, it will not launch in majar mode.
All files in which React JSX is written are not only .jsx extensions.
If you want to lauch the rjsx-mode for all of .js files, you set up like this.

(add-to-list 'auto-mode-alist '(".*\.js\'" . rjsx-mode))

As in the official website, if you run rjsx-mode only for the js file under the components or containers folder, do as this.

(add-to-list 'auto-mode-alist '("components\/.*\.js\'" . rjsx-mode))
(add-to-list 'auto-mode-alist '("containers\/.*\.js\'" . rjsx-mode))

Make the App.jsx file and check it good working.

touch App.jsx

Write this.

import React from 'react';

class App extends React.Component{
  constructor(){
    super();
    this.state = {
      txt: 'this is the state text',
    }
  }

  update(e){
    this.setState({
      txt: e.target.value
    })
  }

  render(){
    return(
      <div>
        <p>Text: {this.state.txt}</p>
        <input name="" type="text" onChange={this.update.bind(this)} />
      </div>
    )
  }
}

export default App;

You can see that the majar mode is “RJSX”

Well, looking at the above image, warning is displayed because there is no semicolon at the end of the line.
I don’t sure it is from ES6, but the semicolon at the end of the line is no longer mandatory.
Disable this warning to edit configuration file and change to indent width to the 2 spaces.

open ~/.emacs.d/init.el file and write this.

(add-hook 'rjsx-mode-hook
          (lambda ()
            (setq indent-tabs-mode nil) ;;Use space instead of tab
            (setq js-indent-level 2) ;;space width is 2 (default is 4)
            (setq js2-strict-missing-semi-warning nil))) ;;disable the semicolon warning

It seems good.
The basic setting is over.

About JSX autocomplete

The rjsx mode does the autocomplete for jsx tags.
In jsx, typing “<” will automatically expand “/>”.

and enter “button”, delete “/” with “C-d”, the close button tag </button> is created.

It is really convenient

Conclusion

I think that React’s major mode will jostle with js2-jsx-mode, web-mode, rjsx-mode etc for a while.
Among them, I thought rjsx-mode was useful.

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執筆者：candle