什么是“返回”;在javascript中意味着什么？ [英] What does "return;" mean in javascript?

问题描述

转过这段代码：

if(!function1()) return;
function2();
function3(array1[index1]);

返回后即时分号是什么意思？我在jquery代码下找到了它。 jquery与它无关吗？

What does having an instant semicolon after return mean? I found it under a jquery code. jquery has nothing to do with it right?

推荐答案

返回语句在Javascript中终止一个函数。这段代码基本上说如果！function1（）（与 function1（）的返回值相反）是 true 或truthy，然后停止执行函数。

The return statement in Javascript terminates a function. This code basically says that if !function1() (the opposite of function1()'s return value) is true or truthy, then just stop executing the funciton.

也就是说，立即终止此函数。分号是javascript中的语句终止符。如果！function1（）最终为 true 或truthy，那么该函数将返回，并且下面没有任何代码将被执行。

Which is to say, terminate this function immediately. The semicolon is a statement terminator in javascript. If !function1() ends up being true or truthy, then the function will return and none of the code below it will be executed.

返回可用于从函数返回值，如：

Return can be used to return a value from a function, like:

function returnFive(){
   return 5;
}

或者，就像在这种情况下，它是一种简单的方法来停止一个功能，如果 - 出于某种原因 - 我们不再需要继续。喜欢：

Or, like in this case, it's an easy way to stop a function if--for some reason--we no longer need to continue. Like:

function isEven(number){
  /* If the input isn't a number, just return false immediately */
  if(typeof number !== 'number') return false;
   /* then you can do even/odd checking here */
}

正如您所怀疑的，这与jQuery没有任何关系。分号在那里，以便Javascript引擎知道有两个语句：

As you suspected, this has nothing to do specifically with jQuery. The semicolon is there so that the Javascript engine knows that there are two statements:

if(!function1()) return;
        function2();

不只是一个陈述，你可以看到它会完全改变程序：

Not just one statement, which you can see would totally change the program:

if(!function1()) return function2();

这篇关于什么是“返回”;在javascript中意味着什么？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！