Set Vs Map in JavaScript

In JavaScript, Set and Map are built-in data structures used to store ordered collections of data, where Set holds unique values and Map stores data as key–value pairs.

• Set: Stores a collection of unique values with no duplicates.
• Map: Stores data as key–value pairs, allowing efficient lookup by keys.

JavaScript Set

JavaScript Set is a collection of unique values accessed without keys, where duplicate entries are not allowed.

• Stores only distinct values.
• Commonly used to remove duplicates from other data structures.

let sample = new Set();
sample.add("Hello");
sample.add(1)
sample.add("Bye")
sample.add("@");

for (let item of sample) {
    console.log(item);
    }

• A new Set named sample is created, and four distinct values are added.
• Iterating over sample with for…of logs each value in the order they were inserted.

Note: Sets store only unique values, so any duplicate additions would be ignored.

Syntax:

new Set([it]);

JavaScript Map

Maps are used to store data in key-value pairs where keys are used to uniquely identify an element and values contain the data associated with it.

• Keys can be of any data type.
• Maintains insertion order for entries.

let sample = new Map();
sample.set("name", "Ram");
sample.set("Role", "SDE")
sample.set("Country", "India")

for (let item of sample) {
    console.log(item);
    }

• A Map is created and key–value pairs are added using set().
• Iteration with for...of prints each entry as [key, value] in order.

Syntax:

new Map([it]);

When to Use Set or Map in JavaScript

• The choice between Set and Map depends on how the data needs to be accessed.
• Use Map when data must be identified and retrieved using keys.
• Use Set when only unique values need to be stored.

Difference between Map and set

Here's the difference between Map and Set: