Q: Unexpected token, expected , in React component I have a React component that looks like this
'use strict';

import 'babel-polyfill';
import React from 'react';
import TreeNode from './TreeView';

export default React.createClass({

  mapFromApi : function(data)  {
    const rec = (tree) => tree.reduce((x,y) => {

      const newObj = {
        "id" : y["@id"],
        "name" : y["rdfs:label"]
      };

      if (y.hasOwnProperty("options")) {
        newObj.children = rec(y.options, []);
      }
      if (y.hasOwnProperty("children")) {
        newObj.children = rec(y.children, []);
      }

      x.push(newObj);
      return x;
    }, []);

    let t = rec(data);

    return t;

  },
  render: function (data) {
    let tree1 = this.mapFromApi(this.props.data.properties).map(child => {
        return <TreeNode key={child['id']} data={child}/>;
    }.bind(this));

    return (
      <div className='vocab'>
      <h4>vocab1</h4>
        <div className='accordion'>
            {tree1}
        </div>
      </div>
    );
  }
});

When I run this I get an error on the bind keyword
SyntaxError: App.jsx: Unexpected token, expected , (56:5)
  54 |     let tree1 = this.mapFromApi(this.props.data.properties).map(child => {
  55 |         return <TreeNode key={child['id']} data={child}/>;
> 56 |     }.bind(this));
     |      ^
  57 |
  58 |     return (
  59 |       <div className='vocab'>

I'm not sure if this has to do with my Babel setup and I'm very confused about the whole es version situation.
Can some one help me resolve this? Many thanks.

A: If you simplify the way this code is laid out, these kind of syntax errors should be easier to identify.
let { data } = this.props;

this
  .mapFromApi(data.properties)
  .map(child => <TreeNode key={child.id} data={child} />)

The arrow function is already going to .bind(this) for you, so you can just omit that.

A: You shouldn't need to use .bind(this) because you are using the ES6 arrow function => and that will reference the correct this
I would write some thing like this
const {data} = this.props;

let tree1 = this.mapFromApi(data.properties).map(child => {
    return <TreeNode key={child['id']} data={child}/>;
});

