Loop inside of a loop, in React JSX

问题

I am trying to render in react, jsx, a loop inside of a loop Like bellow:

{this.state.ans.map(function(item) {
    return (
        {this.state.quest.map(
            function(item1) {return (item1)}
        )}        
        {item}
    )
})}

This does not work any other suggestions

回答1:

You forgot the wrapping div in your first map statement:

render() {
  return (
    <div>
      {this.state.ans.map(item =>
        <div> // this div was missing
          {this.state.quest.map(quest => quest)}
          {item}
        </div>
      )}
    </div>
  )
}

回答2:

Try it like this:

render(){
    return (
        .
        .
        .
        {this.state.ans.map((item) => {
            return (
                <div>
                    {this.state.quest.map((item1) => { 
                           return (item1); 
                        }
                    )}        
                   {item}
               </div>
            );
        })}
    );
}

Basically the idea is that, you should return a single element - in my example a div (with the latest react version you don't have to). And moreover, use lambdas in order for this to reference the correct context.

If you do not use ES6, you can add the following statement at the beginning of the render method:

var that = this;

and use that afterwards with the function(){} syntax inside the return.

来源：https://stackoverflow.com/questions/47632781/loop-inside-of-a-loop-in-react-jsx