Arrow function (e6 js) | Chinese Rule of Eight

For arrow functions, this is picked up from surroundings (lexical).

In other words, Arrow functions are lexically scoped; this means that

their ‘this’ is bound to the context of the surrounding scope

That is to say, whatever ‘this’ refers to can be preserved by using an arrow function.

function Test2() {

//this is used as private

this.name = "Jabba the Hut"; // this will be bound to the global object.

console.log("Test2() Constructor: " + this.name);

var age = 36;

return {

//if we want to use this as public, we have to use self

growls : function(phrase) { //NON ARROW FUNCTION

// 'name' references the property this.name

console.log("Age is: " + age); // can access private variable

growls2 : function(phrase) { // NON ARROW FUNCTION

// this is tied to global, thus, it will use this.name as defined globally

// Due to it not being a arrow function, the property this.name

// and this.name here, are different.

console.log(this.name + " yells out " + phrase);

growls3 : (phrase) => { // ARROW FUNCTION

// correctly uses this to reference the instantiation of this object on the heap

// thus, it will use Test2's property this.name

console.log(this.name + " yells out " + phrase);

}

};

}

var t2 = new Test2(); //own attribute

t2.name = "Ryu..";

t2.growls("hadoken");

t2.growls2("tats makesen bukakyu");

t2.growls3("shoooo ryu ken!");

output:

Test2() Constructor: Jabba the Hut
Age is: 36
Ryu.. yells out tats makesen bukakyu
Jabba the Hut yells out shoooo ryu ken!