Understanding Primitives and References in JavaScript

In JavaScript, values can be categorized into two types: primitives and references.

Primitive Types:

Primitives include:

- String

- Number

- Boolean

- Null

- Undefined

- Symbol

Primitives store values directly in memory.?

Reference Types:

References include:

- Objects

- Arrays

- Functions

References, as the name suggests, store the memory address (or reference) of the object rather than the actual object.

Example 1: Working with Primitives

Let's take a look at an example with primitive types:

let x = 10;

let y = x;

x = 20;        

What do you think the value of y is? It remains 10. This is because x and y are both primitives, and primitives store their values independently. When y is assigned to x, a copy of the value is made. So even when x is changed later, y holds the initial value.

Example 2: Working with Reference Types

Now let’s look at an example with reference types:

let x = { value: 10 };

let y = x;

x.value = 20;        

In this case, if we log y.value, it will be 20. This happens because objects are reference types. Both x and y don’t store the object itself; they store the reference to the object. When you update x.value, you’re modifying the object that both x and y reference, so y reflects the same change.