如何在函数中使用this.id [英] How to use this.id in function

问题描述

没有为this.id分配变量，没有人知道我将this.id传递给findIndex函数的语法吗?

Instead of assigning variable for this.id, does anyone know the syntax of how would I pass this.id into findIndex function?

listing.slideUp(500, function() {
    var listing_id = this.id;
    // I'd like it to say car[0].id == this.id ?
    var index = cars.findIndex(function(car) { return car[0].id === listing_id });
    if (index > -1) {
        cars.splice(index, 1);
    }
});

推荐答案

如果必须使用不支持箭头功能(=>)的浏览器，则可以选择将this绑定到该方法.参考 https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Global_Objects/Function/bind

If you have to use a browser that does not support arrow functions (=>) then an alternative is to bind the this to the method. Ref. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind

var object = {
  id: 'c'
};

console.log(
  $('div').filter(
    function(index, element){
      return element.id == this.id;
    }.bind(object)
  ).get()
);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="b"></div>
<div id="c"></div>
<div id="d"></div>

否则，您只能使用一个箭头函数，该函数不会更改this的上下文.参考 https://developer.mozilla.org/zh- US/docs/Web/JavaScript/Reference/Functions/Arrow_functions

Otherwise you can just us an arrow function, which does not change the context of the this. Ref. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions

var array = ['a', 'c', 'e'];

$('div').on('click', function(){
  array.forEach(id => {
    if (id == this.id) {
      console.log(this);
    }
  });
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="b">b</div>
<div id="c">c</div>
<div id="d">d</div>

这篇关于如何在函数中使用this.id的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！