如何在javascript中使用匿名函数删除新函数

Question

I am trying to replace eval/new Function with corresponding anonymous function.

Existing Code -

var y = 2
var fn = new Function("return" +y)
console.log(fn)

When i print fn output is

ƒ anonymous(
) {
return2
}

Refactored code which i am writing -

var y = 2
var fn1 = function()  {return y}
console.log(fn1)

But fn1 in this case is

ƒ ()  {return y}

Any pointers how can i get the same output as fn ƒ anonymous() {return2} using my own anonymous function.

Answer 1

You can't (at least not without using another version of eval ).

You can get the same effect (ie not having a mutable y ) by using a closure.

 var y = 2 var fn1 = function(closure_y) { return function() { return closure_y; } }(y) y = 3; console.log(fn1())

If your code depends on a function stringifying itself in a particular way, then you should probably rewrite the code so it no longer depends on that.