Let’s not forget about the context

Our program is ready! All the necessary functionality was written! All we have left to do is discuss one more issue.

Inside the methods, we access the properties of computer object computer.property. And what if in the future the name of the object changes and the number of properties increases? We must correct computer everywhere and replace it with something new. Laziness is one of the main qualities of a developer, so I know you don’t want to rewrite any names. It’s good that there is keyword this. It’s the one we will use.

this wasn’t named for nothing. As in a speech, such a pronoun points to a specific object, in JavaScript, the this keyword points to a specific object, namely the object where the function (method) was called.

Using this is easy; all you have to do it replace the name of the object with the keyword in the property reference. Instead of object.property, let’s use this.property.

var cat = {
  name: 'Rudolph',

  introduce: function () {
    console.log('Meow! I’m cat ' + this.name + '!');
  }
};

cat.introduce (); // Logs 'Meow! I’m cat Rudolph!'

The object this points to is called a call context.

Important detail: until the function is called, this does not contain any value; the context appears only when the function is called.

Keyword this is quite advantageous for developers. You will learn later (in the future courses) about other advantages and features of this, but for now we will replace the reference to the properties inside the computer object.