javascript - ReactJS中未定义的函数

Question

不确定我在这里做错了什么，但基础知识是:

/** @jsx React.DOM */

/**
 * Deal with creating a set of posts for a table.
 */
var PostRow = React.createClass({

  handleDelete: function(id){
    var postToDelete = AisisWriter.Models.Post();
    postToDelete.set({id: this});
    posttoDelete.destroy().then(this.deleted, this.fail)
    return false;
  },

  deleted: function() {
    console.log('Success - check the db for this post');
  },

  fail: function() {
    console.log('Fail');
  },

  render: function(){
    // Loop through the post objects.
    var post = this.props.posts.map(function(postObject) {
        var content = null;
        var title = null;

        // Cut off the text at anything over 140 characters
        if (postObject.content.length > 140){
           content = postObject.content.substr(0, 140) + '...';
        }else{
          content = postObject.content;
        }

        // Cut off the text at anything voer 20 characters
        if (postObject.title.length > 20){
          title = postObject.title.substr(0, 20) + '...';
        }else{
          title = postObject.title;
        }

        // Return the rows of the table.
        // React makes us have a unique key.
        return (
          <tr key={postObject.id}>
            <td>{title}</td>
            <td>{content}</td>
            <td>
              <a href={"#/post/" + postObject.id} className="btn btn-primary move-right-10px">View</a>
              <a href={"#/post/" + postObject.id + '/edit'} className="btn btn-success move-right-10px">Edit</a>
              <button className="btn btn-danger" onClick={this.handleDelete(postObject.id)}>Delete</button>
            </td>
          </tr>
        );
    });

    // Finially return the rows (note the div)
    return (
          <div>{post}</div>
      );
  }
});

我遇到的问题是，如果我这样做: this.handleDelete life is grand，页面就会加载。但我需要传入这个特定帖子 id 的 id，所以我尝试执行您所看到的操作: this.handleDelete(postObject.id) 那时我得到: Uncaught TypeError : 总体来说，undefined 不是一个函数，this.handleDelete(postOject.id)。

我是不是已经进入回电 hell 了？我做错了什么吗？

Answer 1

当使用Array.prototype.map时，函数的上下文默认属于全局范围，即 this 引用浏览器中的 window。当您调用 map 时，您可以将上下文传递给它以将其设置为组件，就像您的代码所期望的那样:

// Add a `this` as the second argument to `map` to set the context to
// the current component. `this.handleDelete` will then refer to the component's
// `handleDelete` function like you are expecting.
var post = this.props.posts.map(function(postObject) {
  ...
    <button className="btn btn-danger" onClick={this.handleDelete.bind(this, postObject.id)}>Delete</button>
  ...
}, this);

您还需要bind传递 postObject.id 的回调函数。

// The current form is a function call
this.handleDelete(postObject.id)

// `bind` returns a new function that will be passed `postObject.id` when it is
// called by React.
this.handleDelete.bind(this, postObject.id)