JavaScript Data Types

Key Questions

Primitives

  • Boolean
  • Null (nonexistent object)
  • Undefined (empty variable)
  • Number (integer and floating point)
  • String (words in quotes)
  • Symbol (only in ES6)

Objects

Objects are a reference data type that allow us to group primitives together as an array or hash. There isn't enough room in a variable to store an entire object; instead, we store a reference to another location in memory.

Use the object literal to create objects:

var car = { make: "Tesla", model: "S", year: 2015 };

var cars = [car, { make: "Toyota", model: "Prius", year: 2010 }];

Further Reading

  1. JavaScript data types and data structures [MDN]
  2. Different ways to define an object [SO]
  3. Working with strings

Challenges