How do I access an array that is called from inside a function outside of an object in JavaScript

Question

I'm working with ES 6 and I have a an array assigned to an object like so.

let myArray = [];

further down in my object I have aa function assigned to a handler like so.

myFunction: doSomething

Now outside of the object I define the function.

const doSomething = function(arg){}

So my problem is that when I try to assign something to the array inside of this outer function JavaScript has no idea what that thing is.

I can't figure out how to access this global array inside of the object. So when I to assign a value to this array I get an error.

class myObject {
   var myArray = [],
   myFunction: doSomething,
}

const doSomething = function(arg) {
    let selected = $.map(this.select(), (item) => {
        this.myArray[this.dataItem(item).Id] = true;
    });
}

Answer 1

What you have shown for class myObject is not valid syntax.

You can't declare a variable such as var myArray = [] in a class declaration like that. Similarly, myFunction: doSomething, is not correct either. See the proper ES6 class syntax here on MDN .

If you want to initialize a property on the object, then you can do that inside the constructor with this.myArray = [] and then you can access this.myArray inside any method. Here's is some valid syntax:

class myObject {
   constructor() {
       this.myArray = [];
   }

   myFunction(arg) {
       let selected = $.map(this.select(), (item) => {
           this.myArray[this.dataItem(item).Id] = true;
       });
   }
}

Then, you would use it as:

var x = new myObject();
x.myFunction();

I also notice that the method myFunction assumes there are other methods dataItem() and select() so you would have to define those methods too for this code to work.