Always a This Javascript

always_a_this_javascript.js

// this
console.log(this); // window

function firstFunction() {
  console.log("Hello world"); // Hello world
  console.log(this); //window
}

function Person(name) {
  this.name = "Jane Doe";
  // this.name = name || "Jane Doe"; sets default
  // this.name = name || this.DEFAULT_NAME; also sets default with prototype
  console.log(this);  
}

// Person.prototype.DEFAULT_NAME = "Jane Doe";

// Person.prototype = {
//   DEFAULT_NAME: "Jane Doe",
//   save: function(){
    
//   }
// };
//  Multi-line object. Not recommened as will override other prototypes


// new Person(); { name: "Jane Doe" }
// new is constructor function, creates new object

// Person(); { name: "Jane Doe" }

Person.prototype.save = function() {
  
  var self = this; // Gives access to Person object
  
  $.post("/people", {name: this.name}, function(resp){
    // this == jQxhr
    self.id = resp.id; // this == Person
  }, "json");
};

// -------------- Technique two

Person.prototype.save = function() {
  
  $.post("/people", {name: this.name}, function(resp){
    this.id = resp.id;
  }.bind(this), "json"); // value of this is passed to bind (i.e. Person)

};