JavaScript 访问内部和外部范围内同名的局部变量

Question

Given the following JavaScript:

var someFunction = function(id) {
  //do some stuff
  var modifyId = function(id) {
     //do some stuff
     outer.id = id; //is there any way to modify the id variable in the outer scope from here?
  }
}

How do you modify the id passed into the outer function scope from within the inner function scope?

Answer 1

Unfortunately you can't. By naming the parameter in the nested function id , you've shadowed the parameter in the outer function. Javascript contains no facility for accessing the shadowed name. The only option is to choose a different name for one of the variables.

Answer 2

No, there isn't. From within a function, there's no way (something weird in Mozilla's code or ES5 aside) to refer to the scope as a context in any explicit way, and there's no way to climb up the lexical scope chain in any direct way.

Good question though.

Answer 3

为什么不能只重命名变量之一？

Answer 4

var someFunction = function(id) {
  //do some stuff
  var oid = id;
  var modifyId = function(id) {
     //do some stuff
     // you can access the outer id via the oid variable
  }
}

But, yes, you should just rename one of the formal parameters.