How to access this encapsulated value?

Question

How to access this encapsulated value?

I am using a method wich belongs to a module as a callback in a function from my server.

From this method, i need to access an array encasulated in the module (MyArray).

I can't use this since it refers to the original function (someFunction in my example). But i don't understand why i can't use the that: this feature in this case (that is undefined).

MyModule.js

module.exports = {
  MyArray: [],
  that: this,
  test: functiion() {
    //How to access MyArray ?
  }
};

server.js

var MyModule = require('MyModule');
someFunction(MyModule.test);

node.js

Answer 1

this.MyArray works.

MyModule.test is bound to a this equal to module.exports

You can also just use local variables inside your module.

MyModule.js

var MyArray = [];

module.exports = {
  test: function() {
    // MyArray is accessible
  }
};

And you could also use module.exports.MyArray.

Answer 2

You can use bind to bind the this you want to that function so that even when it's used as a callback the this is correct:

MyModule.js

module.exports = {
  MyArray: []
};
module.exports.test = (function() {
  console.log(this.MyArray); // works here even when not called via MyModule.test
}).bind(module.exports);