JavaScript Composite Types

In JavaScript, composite types (also known as non-primitive types) are objects used to store collections of data or more complex entities. They can hold multiple values and are mutable. Here are the main composite types in JavaScript:

1. Object

• A collection of key-value pairs.
• Values can be of any type, including other objects.
• Example:

  let person = {
    firstName: "John",
    lastName: "Doe",
    age: 30
  };
  

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2. Array

• A special type of object used to store ordered lists of values.
• Values can be accessed by their index.
• Example:

  let fruits = ["Apple", "Banana", "Cherry"];
  console.log(fruits[0]); // "Apple"
  

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3. Function

• A block of code designed to perform a particular task and is an object in JavaScript.
• Functions can be assigned to variables, passed as arguments, and returned from other functions.
• Example:

  function greet(name) {
    return "Hello, " + name;
  }
  console.log(greet("John")); // "Hello, John"
  

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4. Date

• Represents a date and time.
• Example:

  let date = new Date();
  console.log(date); // Current date and time
  

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5. RegExp (Regular Expression)

• Represents a regular expression, used for pattern matching within strings.
• Example:

  let pattern = /google/i;
  

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6. Map

• A collection of key-value pairs where keys can be of any type.
• Example:

  let map = new Map();
  map.set("name", "John");
  map.set("age", 30);
  

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7. Set

• A collection of unique values.
• Example:

  let set = new Set();
  set.add("Apple");
  set.add("Banana");
  

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Characteristics of Composite Types:

• Mutable: Their values can be changed after creation.
• Stored by Reference: When assigned or passed, they reference the same memory location.

Understanding composite types is essential for working with complex data structures and functionality in JavaScript.