What types of data can be considered complex?

Complex (object) data types in JavaScript include:

• Objects (Object): Ordered collections of key-value pairs. They can contain functions, arrays, and other objects.

  // Example object
  const person = {
      name: 'John',
      age: 30
  };
  

• Arrays (Array): A special type of object designed to store ordered collections of elements.

  // Example array
  const numbers = [1, 2, 3, 4, 5];
  

• Functions (Function): Objects that can be invoked to execute specific code.

  // Example function
  const greet = function(name) {
      console.log('Hello, ' + name);
  };
  

• Dates (Date): Objects for working with time and dates.

  // Example Date
  const now = new Date();
  

• Regular Expressions (RegExp): Objects for working with text patterns.

  // Example RegExp
  const pattern = /abc/;
  

• Maps (Map): Collection of key-value pairs where keys can be of any data type.

  // Example Map
  const myMap = new Map();
  myMap.set('a', 1);
  myMap.set('b', 2);
  

• Sets (Set): Collection of unique values of any type.

  // Example Set
  const mySet = new Set([1, 2, 2, 3]); // Contains only 1, 2, 3
  

• Symbols (Symbol): Unique and immutable primitive values that can be used as property keys to avoid naming conflicts. Although Symbol is a primitive by nature, it is often considered a complex type due to its specific use in objects and its uniqueness, which distinguishes it from other primitives.

  // Example Symbol
  const mySymbol = Symbol('description');
  const obj = {
      [mySymbol]: 'unique value'
  };
  

Unlike primitive types, complex data types are stored in memory by reference.