Question

在下面的javascript代码中，我想知道哪个对象有＆＃34;这个＆＃34;指向。但我得到了一个功能。

我想＆＃34;这个＆＃34;总是提到调用该函数的对象。所以有人能解释为什么会出现这种情况吗？

＆＃13;

$(document).ready(function() {

  var Paper = function() {};

  Paper.prototype = {
    populate: function(data) {
      data.questions.forEach(function(entry) {
        //printing a function instead of object
        console.log(this);
      }.bind(this));
    }
  };


  var paperDataLoader = function() {
    this.callbacks = [];
  };

  paperDataLoader.prototype = {

    //accepts a callback to notify the registered function
    registerDataLoaded: function(callback) {
      this.callbacks.push(callback);
    },

    //calls the callback functions when data is loaded
    loadData: function() {
      $.ajax('../find_paper.php', {
        method: 'POST',
        contentType: 'text'
      }).done(function(ajaxData) {
        this.paperData = $.parseJSON(ajaxData);
        for (var i = 0; i < this.callbacks.length; i++)
          this.callbacks[i](this.paperData);
      }.bind(this));
    }
  };


  var loader = new paperDataLoader();
  var paper = new Paper();
  loader.registerDataLoaded(paper.populate);
  loader.loadData();
});

＆＃13;

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

＆＃13;

Answer 1

它为我工作：

var Paper = function() {};

Paper.prototype = {
    populate: function(data) {
        data.questions.forEach(function(entry) {
            console.log(this);
        }.bind(this));
    }
};

var paper = new Paper();
paper.populate({ questions: [ 1 ] }); // prints paper object

也许你在某个地方重新绑定paper.populate？

＆＃34;这＆＃34;返回函数而不是对象

1 个答案: