In JavaScript, Set and Map are two types of objects that are used for storing data in an ordered manner. Both these data structures are used to store distinct types of data inside the same object. In Maps, the data is stored as a key-value pair whereas in Set data is a single collection of values that are unique.
Let’s learn about the uses of these two data structures.
JavaScript Set: It is a collection of values that can be accessed without a specific key. The elements are unique and the addition of duplicates is not allowed. Sets are mostly used to remove duplicates from any other data structure
Syntax:
new Set([it]);
Example: In this example, we will learn how to implement a set
Javascript
let sample = new Set();sample.add("Hello");sample.add(1)sample.add("Bye")sample.add("@");for (let item of sample) { console.log(item); } |
Output:
Hello 1 Bye @
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.
Syntax:
new Map([it])
Example: In this example, we will implement a map.
Javascript
let sample = new Map();sample.set("name", "Ram");sample.set("Role", "SDE")sample.set("Country", "India")for (let item of sample) { console.log(item); } |
Output:
["name","Ram"] ["Role","SDE"] ["Country","India"]
What to use?
Choosing one data structure among these two depends on the usage and how we want to access the data. If we want the data to be identified by a key then we should opt for maps but if we want unique values to be stored then we should use a set.
| Map | Set |
|---|---|
| It is a collection of key-value | It is a collection of unique elements |
| Map is two-dimensional | The set is one dimensional |
| Values are accessed using keys | In-built methods are used to access values |
