今天,在检查Jasmine的源代码here时,我偶然发现了以下内容：

if (queueableFn.timeout) {
    timeoutId = Function.prototype.apply.apply(self.timeout.setTimeout, [j$.getGlobal(), [function() {
      var error = new Error('Timeout - Async callback was not invoked within timeout specified by jasmine.DEFAULT_TIMEOUT_INTERVAL.');
      onException(error);
      next();
    }, queueableFn.timeout()]]);
}

我对为什么在这里为什么两次调用apply感到很感兴趣.

解决方法:

commit that introduced this syntax解释了一切：

Older IE fixes Still not green, but getting close. Summary of Older
IE discrepancies:

• Older IE doesn’t have apply/call on the timing functions
• Older IE doesn’t allow applying falsy arguments
• Older IE doesn’t allow setting onclick to undefined values
• Older IE doesn’t have text property on dom nodes