gistfile1.js

var pureRender = (Component) => {
  Object.assign(Component.prototype, {
    shouldComponentUpdate (nextProps, nextState) {
      return !shallowEqual(this.props, nextProps) ||
             !shallowEqual(this.state, nextState);
    }
  });
};

module.exports = pureRender;

///////////////////////////////////////////////////
var pureRender = require('./pureRender');

class Foo extends React.Component {
  render () {
    return <div>this ain’t so bad</div>
  }
}

pureRender(Foo); // don't return so you know its mutative :(

module.exports = Foo;

@benmosher , how do you know whether props or state is updated? Component should rerender in either case, right?

Unfortunately this.state of the child becomes meaningless in the above implementation.

If you really want to do this right, you'll need to pass this.setState() as a prop to the child component, and make it use it like this.props.setState() instead of the child's own this.setState().

j/k this won't work

updated, I can't think of a very declarative way to do this except to mutate the prototype or inherit :\

@ryanflorence You can still Object.assign({}, ...) and return a mutated clone.

How do you feel about this approach?

class Foo extends React.Component {
  constructor(props) {
    super(props);
    this.shouldComponentUpdate = React.addons.PureRenderMixin.shouldComponentUpdate.bind(this);
  }
  render () {
    return <div>Helllo</div>
  }
}

@aputinski you get a gold star for simplest possible solution :-)

In any cases that are more complex than a single lifecycle hook, this doesn't work as well.

@RickWong methods on es6 classes aren't enumerable, but you could do Object.assign(Object.create(Foo), {should...})

Does the latest gist work without any issues? Hard to tell by the comments. :)

@aputinski 👍

@aputinski +1

Won't be easier just extending Component?

class PureRenderComponent extends React.Component {
  shouldComponentUpdate () {
    return React.addons.PureRenderMixin.shouldComponentUpdate.apply(this, arguments)
  }
}

class Foo extends PureRenderComponent {
  render () {
    return (<div>Pure</div>)
  }
}

Sorry to pile on, but this is one of the top hits when searching for PureRenderMixin in ES6, my two cents:

const pure = function (target) {
  target.prototype.shouldComponentUpdate = React.addons.PureRenderMixin.shouldComponentUpdate;
  return target;
}

@pure
class Test extends React.Component { }

E.g. https://jsbin.com/zayoda/4/edit?js,console,output

Hi, is the code provided by @aputinski still works? I'm using react 15.0.1 and it doesn't work for me.

@jameswnl
From official docs:

import PureRenderMixin from 'react-addons-pure-render-mixin';
class FooComponent extends React.Component {
  constructor(props) {
    super(props);
    this.shouldComponentUpdate = PureRenderMixin.shouldComponentUpdate.bind(this);
  }

  render() {
    return <div className={this.props.className}>foo</div>;
  }
}

You need to install the addon as well.

@brigand
Can you elaborate on your statement "In any cases that are more complex than a single lifecycle hook, this doesn't work as well".

What exactly are the drawbacks to this same approach that is also now listed in the official React docs?