传递正确的“这个”上下文setTimeout回调？ [英] Pass correct "this" context to setTimeout callback?

问题描述

如何将上下文传递到 setTimeout ？我想在1000毫秒后调用 this.tip.destroy（）如果 this.options.destroyOnHide 如何做到这一点？

How do I pass context into setTimeout? I want to call this.tip.destroy() if this.options.destroyOnHide after 1000 ms. How can I do that?

if (this.options.destroyOnHide) {
     setTimeout(function() { this.tip.destroy() }, 1000);
} 

当我尝试上述， this 指代窗口。

When I try the above, this refers to the window.

推荐答案

您需要保存对 setTimeout 执行函数调用，因为 setTimeout 执行函数 this 全局对象：

You need to save a reference to the context where the setTimeout function call is made, because setTimeout executes the function with this pointing to the global object:

var that = this;
if (this.options.destroyOnHide) {
     setTimeout(function(){that.tip.destroy()}, 1000);
} 

你可以很容易地证明 setTimeout set

You can easily prove that setTimeout set this to the global object by:

(function () {
  alert(this); // alerts hello
  setTimeout(function(){
    alert(this == window); // true
  }, 1000);
}).call("hello");

另请参阅：

• setTimeout - 这个问题

• setTimeout - The 'this' problem

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