JavaScript chapters

Chapter 12 of 17

Objects and Structures

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Grouping related data

When a value is more than a single number — a user with a name, email and age — you want to bundle the fields together under one name. JavaScript provides objects (or structs / records / dictionaries depending on the language) to do exactly that.

const user = {
  name: "Aman",
  age: 20,
  greet() { return "Hi " + this.name; }
};
console.log(user.greet());

Methods

Many languages let an object carry not only data but also functions ("methods") that operate on that data. This style is called object-oriented programming and is the dominant way to organise large programs.

When to make a new type

If you find yourself passing three or four related values into every function — say x, y and z of a 3-D point — that is a clear signal to introduce a new object type that holds them together. The code becomes shorter, safer and easier to extend.

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