If the props for a child component are unchanged, does React still re-render it?

Question

Suppose I have the following pairing of parent and child components in React:

var ChildComponent = React.createClass({
    getDefaultProps: function(){
        r         


        

Answer 1

When React re-renders ParentComponent it will automatically re-render ChildComponent. The only way to get around is to implement shouldComponentUpdate in the ChildComponent. You should compare this.props.a, this.props.b and this.props.c and ChildComponents own state to decide to re-render or not. If you are using immutable data than you can just compare previous and next state and props using strict equality ===.

There are a few thing to note with your code

1. You dont need to forceUpdate when you setState. React automatically does it for you.

2. You probably meant:

   <ChildComponent a={this.props.a} b={this.props.b} c={this.props.c}/>