React JSX：遍历哈希并为每个键返回JSX元素

Question

我正在尝试遍历哈希中的所有键，但是循环没有返回任何输出。console.log()预期的输出。知道为什么JSX没有返回并输出正确吗？

var DynamicForm = React.createClass({
  getInitialState: function() {
    var items = {};
    items[1] = { name: '', populate_at: '', same_as: '', 
                 autocomplete_from: '', title: '' };
    items[2] = { name: '', populate_at: '', same_as: '', 
                 autocomplete_from: '', title: '' };
    return {  items  };
  },



  render: function() {
    return (
      <div>
      // {this.state.items.map(function(object, i){
      //  ^ This worked previously when items was an array.
        { Object.keys(this.state.items).forEach(function (key) {
          console.log('key: ', key);  // Returns key: 1 and key: 2
          return (
            <div>
              <FieldName/>
              <PopulateAtCheckboxes populate_at={data.populate_at} />
            </div>
            );
        }, this)}
        <button onClick={this.newFieldEntry}>Create a new field</button>
        <button onClick={this.saveAndContinue}>Save and Continue</button>
      </div>
    );
  }

Answer 1

Object.keys(this.state.items).forEach(function (key) {

Array.prototype.forEach()不返回任何内容- .map()而是使用：

Object.keys(this.state.items).map(function (key) {
  var item = this.state.items[key]
  // ...