从成员函数访问函数成员变量

Question

Foo is a function with a public member called list. It has a public member function called setList. I want to be able to edit list from setList. Can I do that? I've attempted a few things, but I haven't been able even to access list from inside setList.

var Foo = function Foo() {

    this.list = ["a", "b", "c"];

    this.setList = function(data) {
        // Attempt 1
        console.log(list); // Uncaught ReferenceError: list is not defined
        // Attempt 2 
        console.log(this.list); // undefined
        // Attempt 3
        console.log(Foo.list); // undefined
    }
}

I'm still figuring JS out, so please forgive me if I've called something by the wrong name.

Answer 1

Assuming you're creating instances with Foo :

function Foo()
{
    this.list = ["a", "b", "c"];

    this.setList = function(data) {
        this.list = data;
    }
}

var x = new Foo();
console.log(x.list); // a,b,c
x.setList([]);
console.log(x.list); // empty array

Answer 2

You could also set a prototype which will yield the same results. I could explain reasons why sometimes you may want to use a prototype, but this link provides good information on that subject http://thecodeship.com/web-development/methods-within-constructor-vs-prototype-in-javascript/

function Foo(){
  this.list = [1,2,3];
}

Foo.prototype = {
  setList: function(data){
    this.list = data;
  }
};

var x = new Foo();
x.setList(['hello', 'hi']);
console.log(x.list);

this will log the array passed into x.setList which is ['hello', 'hi'] showing that list was update.