♻️ React Style Guide 📜

A best practices style guide for managing sane react components.

React.js

Components

• ###Organization

  // ES6
  // Use es6 import syntax and destructor if you need to.
  import React from 'react';
  import {Route, DefaultRoute, NotFoundRoute} from 'react-router';
  
  // ES5
  var React = require('react');
  var Router = require('react-router');
  
  var Route = Router.Route;
  var DefaultRoute = Router.DefaultRoute;
  var NotFoundRoute = Router.NotFoundRoute;
  
  //<PeopleList />
  //    |
  //    V
  var Person = React.createClass({
      
      // Defaults and initialization properties at the top
      propTypes: {},
      getInitialState: function() {},
      getDefaultProps: function() {},
  
      // Life-cycle methods here
      componentWillMount: function() {},
      componentWillReceiveProps: function() {},
      componentWillUnmount: function() {},
  
      // Instance methods (any application logic should be refactored out into the Store)
      someHelperMethod: function() {},
      someOtherInstanceMethod: function() {},
      dynamicCss: function() {},
  
      // The most important method in a react class. Make sure to keep it simple as possible.
      render : function() {},
      
      // Actions handlers underneath render() prefixed with _
      _addPoints: function() {}
  
  })

• Props & State

  • Don't pass props to state.

      componentDidMount: function(){
        this.setState({ people: this.props.people })
        // BAD: usually a code smell if you're pass down props to state.
      }

  • Note: replaceState effects entire state, setState merges with the current state.

       this.setState({ isEditing: true });
       ... (later) ... 
       this.replaceState({ isActive: true }); // isEditing no longer part of current state
       this.setState({ isActive: true }); // isActive merges into current state

• ###Comments

  • Write a comment at the top of the component class if the component belongs to a parent component, especially if the parent component is passing in props.

• ###Methods

• Class instance methods should do one thing. (Single Responsibility Principle)

• Don't change state in a child component without letting the parent component know. Deeply nested components are really hard and can be confusing at times if you use too much state and instead of using props data.

• Use less state and more this.props in your render method.

• Learn about .bind(); because you're most likely going to be using a scoped this in a function inside of a function.

  render: function(){
    var editPositionState = function () {
      // this.props is undefined
      return this.props.stage.position === this.state.editPosition;  
    };
    var editPositionState = function () {
      // this.props works!
      return this.props.stage.position === this.state.editPosition;
    }.bind(this);
    // or you can do it the lame way and grab this.props
    // before a function and assign it to a variable.
  }

  • or if your using a ES6 transpiler like Babeljs use arrow functions to keep the correct context.

  render: function(){
    var editPositionState = () => {
      // this.props works!
      return this.props.stage.position === this.state.editPosition;
    }
  }

• Use multi-line jsx if a component has more than two properties.

  <Component
    propertyOne={...}
    propertyTwo={...}
    propertyThree={...}
    …
  />

• Don't get fancy with manipulating child DOM elements. Map over them and create child components instead.

  // Good
  render: function() {
    var people = this.props.people.map(function (person) {
      if (person){
        return (
          <Person
            person = {person}
            handleUpdate = {this.handleUpdate}
            key = {person.id}/>
        );
      }
    }, this);
  
    return (
      <ul>
        {people}
      </ul>
    )
  }
  
  //Better
  render: function() {
  
    return (
      <ul>
        {
          this.props.people.map(function (person) {
            if (person){
              return (
                <Person
                  person = {person}
                  handleUpdate = {this.handleUpdate}
                  key = {person.id}/>
              );
            }
          }, this);
        }
      </ul>
    )
  }

  • If it's a simple iteration over an array, render out each of the elements in an array inside jsx.

Mixins

• Don't use mixins.. thinking about composable components instead. Mixins will get deprecated

CSS styles in your components

• Useful when you're creating dynamic css styles for your components and it can be fun!
• CSS should be unique for a component.
• Abstract your css into a class method if it's dynamic CSS.
• Throw in that class method of all your inline styles defined into style={...}

    cssStyles: function(){...},
    
    render: function(){
      return (
        <div style={this.cssStyles()}
          css styles created in JS!
        </div>
      )
    }

Testing

• Jest best practices...

Tools

• React dev console chrome extension
• react-rails gem (if you're using rails)
• an editor that supports vertical split screens for managing hiearchy and thinking about one-way data flow.

Other guides

airbnb's react/jsx style guide

React Native

• TBA