react-autobind-component

Use this alternative to React.Component to automatically bind your methods.

TL;DR

When using react-autobind-component instead of React.Component, the onClick() method gets automatically bound, so this.foo will be bar:

import React from 'react';
import AutoBindComponent from 'react-autobind-component'; // <--

class Button extends AutoBindComponent {
    foo = 'bar';

    onClick() {
        this.foo;
        // -> 'bar'
    }

    render() {
        return (
            <button onClick={this.onClick}>
                Click here
            </button>
        );
    }
}

Use case

Problem:

import React, { Component } from 'react';

class Button extends Component {
    foo = 'bar';

    onClick() {
        this.foo;
        // -> undefined, because `this` refers to the caller of onClick
    }

    render() {
        return (
            <button onClick={this.onClick}>
                Click here
            </button>
        );
    }
}

How you are used to solve this:

import React, { Component } from 'react';

class Button extends Component {
    foo = 'bar';

    constructor(props) {
        super(props);
        this.onClick = this.onClick.bind(this); // <- old solution
    }

    onClick() {
        this.foo;
        // -> 'bar'
    }

    render() {
        return (
            <button onClick={this.onClick}>
                Click here
            </button>
        );
    }
}

How you are going to solve this from now on:

import React from 'react';
import AutoBindComponent from 'react-autobind-component'; // <- new solution

class Button extends AutoBindComponent {
    foo = 'bar';

    onClick() {
        this.foo;
        // -> 'bar'
    }

    render() {
        return (
            <button onClick={this.onClick}>
                Click here
            </button>
        );
    }
}

How does it work?

Very simple:

import { Component } from 'react';
import bindAll from 'lodash-bindall';

export default class AutoBindComponent extends Component {
    constructor() {
        super();
        bindAll(this, Object.getOwnPropertyNames(this.__proto__));
    }
};

The real version is slightly smarter, since it skips binding for methods like constructor, componentWillMount, render, etc.