All map methods using JavaScript

In this article, we will learn all the methods related to the map.

But first, what is a map?

The Map object holds key-value pairs and remembers the original insertion order of the keys. Any value (both objects and primitive values) may be used as either a key or a value. (MDN Definition)

How to creata map

Well, now we know the general definition of a map, but how do we create a map?

its very easy

const map = new Map([]);

console.log(map);
// Map(0) {}

Now we have created a map, but there are no elements in it, so how do we add an element?

Add elements to a Map

We can use set method to add elements to map.

Example

// Map
const map = new Map();

// Set elements
map.set('name', 'John');
map.set('age', 30);

// Result:
console.log(map);

Output

Map(2) { 'name' => 'John', 'age' => 30 }

Can we update this element? Yes we can

Update an element in a map

We can also easily update the element in the map using set method.

// Map
const map = new Map([
    ['name', 'John'],
    ['age', 30]
]);

// Update an element if exists
map.set('name', 'Doe');

// Add new element (because not exists)
map.set('country', 'USA');

Output

Map(3) { 'name' => 'Doe', 'age' => 30, 'country' => 'USA' }

Well, if we want to delete an element from the map, can we do that? Yes we can

Delete an element from a map

We can delete an element from a map using delete method.

Example

// Map
const map = new Map([
    ['name', 'John'],
    ['age', 30],
    ['country', 'USA']
]);

// before deletion
console.log(map);

// delete an elemetn
map.delete('country');

// after deletion
console.log(map);

Output

Map(3) { 'name' => 'John', 'age' => 30, 'country' => 'USA' }
Map(2) { 'name' => 'John', 'age' => 30 }

And if we want to delete all elements, will we delete every item? The answer is no

Delete all elements from map

We can delete all elements from map using clear method

Example

// Map
const map = new Map([
    ['name', 'John'],
    ['age', 30],
    ['country', 'USA']
]);

// Clear
map.clear();

// Result:
console.log(map);

Output

Map(0) {}

Get an element from a Map

You can use the get() method to get elements from a Map

// Map
const map = new Map([
    ['name', 'John'],
    ['age', 30],
    ['country', 'USA']
]);

// Get an element
console.log(map.get('name'));

Output

John

Get the number of elements in a map

We can get the number of elements using size property.

Example

// Map
const map = new Map([
    ['name', 'John'],
    ['age', 30],
    ['country', 'USA']
]);

// Result:
console.log(map.size);

Output

3

Check if an element exists in a Map

We can check if an elements exists using has method.

Example

const map = new Map([
    ['name', 'John'],
    ['age', 30],
    ['country', 'USA']
]);

console.log(map.has('name'));
console.log(map.has('isMarried'));

Output

true
false

Thank you for reading

Thank you for reading my blog. 🚀