javascript/react

Airbnb React/JSX Style Guide

A mostly reasonable approach to React and JSX

Table of Contents

1. Basic Rules
2. Naming
3. Declaration
4. Alignment
5. Quotes
6. Spacing
7. Props
8. Parentheses
9. Tags
10. Ordering

Basic Rules

• Only include one React component per file.
• Always use JSX syntax.
• Do not use React.createElement unless you're initializing the app from a .js file.

Naming

• Extensions: Use .jsx extension for React components.

• Filename: Use PascalCase for filenames. E.g., ReservationCard.jsx.

• Reference Naming: Use PascalCase for React components and camelCase for their instances:

  // bad
  const reservationCard = require('./ReservationCard');
  
  // good
  const ReservationCard = require('./ReservationCard');
  
  // bad
  const ReservationItem = <ReservationCard />;
  
  // good
  const reservationItem = <ReservationCard />;
  

  Component Naming: Use the filename as the component name. So ReservationCard.jsx should have a reference name of ReservationCard. However, for root components of a directory, use index.jsx as the filename and use the directory name as the component name:

  // bad
  const Footer = require('./Footer/Footer.jsx')
  
  // bad
  const Footer = require('./Footer/index.jsx')
  
  // good
  const Footer = require('./Footer')
  

Declaration

• Do not use displayName for naming components, instead name the component by reference.

  // bad
  export default React.createClass({
    displayName: 'ReservationCard',
    // stuff goes here
  });
  
  // good
  const ReservationCard = React.createClass({
    // stuff goes here
  });
  export default ReservationCard;
  

Alignment

• Follow these alignment styles for JSX syntax

  // bad
  <Foo bar="bar"
       baz="baz" />
  
  // good
  <Foo
    bar="bar"
    baz="baz"
  />
  
  // if props fit in one line then keep it on the same line
  <Foo bar="bar" />
  
  // children get indented normally
  <Foo
    bar="bar"
    baz="baz"
  >
    <Spazz />
  </Foo>
  

Quotes

• Always use double quotes (") for JSX attributes, but single quotes for all other JavaScript.

  // bad
  <Foo bar='bar' />
  
  // good
  <Foo bar="bar" />
  
  // bad
  <Foo style={{ left: "20px" }} />
  
  // good
  <Foo style={{ left: '20px' }} />
  

Spacing

• Always include a single space in your self-closing tag.

  // bad
  <Foo/>
  
  // very bad
  <Foo                 />
  
  // bad
  <Foo
   />
  
  // good
  <Foo />
  

Props

• Alphabetically order your props.

  // bad
  <Foo
    className="bar baz"
    bar="bar"
  />
  
  // good
  <Foo
    bar="bar"
    className="bar baz"
  />
  

Parentheses

• Wrap JSX tags in parentheses when they span more than one line:

  /// bad
  render() {
    return <MyComponent className="long body" foo="bar" >
             <MyChild />
           </MyComponent>;
  }
  
  // good
  render() {
    return (
      <MyComponent className="long body" foo="bar">
        <MyChild />
      </MyComponent>
    );
  }
  
  // good, when single line
  render() {
    const body = <div>hello</div>;
    return <MyComponent>{body}</MyComponent>;
  }
  

Tags

• Always self-close tags that have no children.

  // bad
  <Foo className="stuff"></Foo>
  
  // good
  <Foo className="stuff" />
  

• If your component has multi-line properties, close its tag on a new line.

  // bad
  <Foo
    bar="bar"
    baz="baz" />
  
  // good
  <Foo
    bar="bar"
    baz="baz"
  />
  

Ordering

• Always follow the following order for methods in a react component:

1. displayName
2. mixins (as of React v0.13 mixins are deprecated)
3. statics
4. propTypes
5. getDefaultProps
6. getInitialState
7. componentWillMount
8. componentDidMount
9. componentWillReceiveProps
10. shouldComponentUpdate
11. componentWillUpdate
12. componentWillUnmount
13. clickHandlers or eventHandlers like onClickSubmit() or onChangeDescription()
14. gettter methods for render like getSelectReason() or getFooterContent()
15. Optional render methods like renderNavigation() or renderProfilePicture()
16. render

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