Essential JavaScript

Objects vs Primitives

Objects are different from values we have worked with so far.

Numbers, strings, Boolean values, and undefined are all primitives. These are the most basic data types available to us, and they are the building blocks for any more complex data structure we want to work with.

The typeof Operator

We can check the data type of any value with the typeof operator. Using typeof will give us a string:

console.log(typeof 42); // "number"
console.log(typeof '42'); // "string"
console.log(typeof true); // "boolean"
console.log(typeof undefined); // "undefined"

We can also use the typeof operator to check the type of an object:

const person = {
  firstName: 'John',
  lastName: 'Doe',
console.log(typeof person); // "object"

No matter what properties an object has, typeof will tell us it is an "object".

Learning Goals

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