Javascript - 从第三方调用函数

Question

为什么这可能是未定义的，我该如何解决？

var a = 1;
var b = 1 + function(){ return 10; }// This could be the wrong way to do it. But it could come from a third party, so it's undeterminded when it's returning. S
console.log(b);

Answer 1

如果你想让这个功能起作用，你必须执行它：

var a = 1;
var b = 1 + function(){ return 10; }()// This could be the wrong way to do it. But it could come from a third party, so it's undeterminded when it's returning. S
console.log(b);

注意我在函数后添加了（）。

Answer 2

您必须调用该函数。

var a = 1;
var b = 1 + (function(){ return 10; })()
console.log(b);