Question

我相信你已经经历了很多次，但我无法弄清楚一个真正符合我需要的线索。

我怎样才能让var inner在上面工作？

function outerOne(){

/* do something*/

    var inner = function(){
            return true 
    }; inner();

};
outerOne()


function outerTwo(){
    if (inner==true)
/* do something*/
};
outerTwo();

请注意，我知道可以将var x声明为外部以使其全局化。但我想要实现的是从函数内部获取var的范围

Answer 1

你试过了吗？

var x;
function outerOne(){

    /* do something*/

    var inner = function(){
        x = 5
        console.log(x + "  Works in inner()");       
    }; 
    inner();

    console.log(x + "  Works in outerOne()");
};
outerOne();

function outerTwo(){
    console.log(x + "  Works in outerTwo()");
};
outerTwo();

函数仅与在其父作用域中声明的变量共享作用域。

修改

为了完整起见，我可以补充说，没有什么能阻止你从函数中返回值：

function outerOne(){ /* do something*/ var inner = function(){ var x = 5 console.log(x + " Works in inner()"); return x; }; var x1 = inner(); console.log(x1 + " Works in outerOne()"); return x1; }; var x2 = outerOne(); function outerTwo(){ console.log(x2 + " Works in outerTwo()"); }; outerTwo();

Answer 2

也许您可以将代码重组为类似

的代码

var obj = 
    {
        outerOne : function(){return true;//or whatever logic you need here
                          },

        outerTwo : function(){  
           if(this.outerOne() === true){
               //do something
           }
        }
    }

    obj.outerTwo();

Answer 3

将您的代码包裹在IIFE中。并将inner设置为顶部的未定义变量。

(function(){
var inner;

  function outerOne(){
  /* do something*/

      inner = function(){
         return true 
      }; inner();
  };
  outerOne()

  function outerTwo(){
      if (inner==true){
        //inner has been set to true, do something
      }
      else{
        //Inner has not been set to true, do something else
      }
  };
  outerTwo();

})();

Answer 4

使变量'x'全局外部函数。

var x = 0; 
function outerOne(){   
 //code block

var inner = function(){
        x = 5
       console.log(x + "  Works in inner()");       
}; inner();
console.log(x + "  Works in outerOne()");
};
outerOne()


function outerTwo(){
console.log(x + "  Works in outerTwo()");
};
outerTwo();

将内部var的范围扩展到另一个函数中

4 个答案: