JavaScript Map Object

In JavaScript, a Map is a built-in object designed to hold key-value pairs. Unlike plain objects, a Map allows keys of any type (including objects, functions, and primitives), and it maintains the order in which keys are inserted.

Why Use Map Instead of Object?

• Maps can use any value as a key.
• Maps maintain insertion order.
• Maps provide reliable size and iteration methods.

Creating a Map

Setting Key-Value Pairs

Getting Values

Checking for Keys

Getting Map Size

Deleting a Key

Clearing All Entries

Iterating Over a Map

Using for...of Loop

Using forEach()

Example: Counting Word Frequency with Map

Key Takeaways

• Map keys can be any data type.
• Maps maintain insertion order.
• Use .set(), .get(), .has(), .delete(), and .clear() to manage entries.
• Maps are ideal for high-performance key-value storage with flexible key types.