In this article, we are given a Map and the task is to get the keys of the map into an array using JavaScript. We can access the keys by using the Map keys() method.
We have a few methods to do this that are described below:
- Using array.from() Method
- Using [ …Map.keys() ] Method
- Using for…of Loop
- Using Map.forEach() Method
Approach 1: Using array.from() Method
- Declare a new map object
- Display the map content
- Use the keys() method on Map Object to get the keys of Map.
- Then use the array.from() method to convert a map object to an array.
Example 1: This example uses an array.from() method to get the keys of the Map in the array.
Javascript
let myMap = new Map().set('GFG', 1).set('Geeks', 2);let array = Array.from(myMap.keys());//Return the length of arrayconsole.log(array.length); |
Output
2
Approach 2: Using [ …Map.keys() ] Method
- Declare a new map object
- Display the map content
- Use the [ …myMap.keys() ] method on Map Object to get the keys of Map as an array.
Example 2: This example uses the [ …Map.keys() ] method to get the keys of the Map in the array.
Javascript
let myMap = new Map().set('GFG', 1).set('Geeks', 2);let array = [...myMap.keys()];//return the length of arrayconsole.log(array.length); |
Output
2
Approach 3: Using for…of Loop Method
- Create an empty array
- By using the for…of Loop, we can iterate over the keys
- At each iteration, we can push the key into an array.
Example:
Javascript
let myMap = new Map().set('GFG', 1).set('Geeks', 2).set('Geeksforneveropen',3);let arr =[];for (let key of myMap.keys()) { arr.push(key);}console.log(arr); |
Output
[ 'GFG', 'Geeks', 'Geeksforneveropen' ]
Approach 4: Using Map.forEach() Method
- Create an empty array
- Use Map.forEach() method for iterating over the loop
- then push the keys into an array
Example:
Javascript
let myMap = new Map().set('GFG', 1) .set('Geeks', 2) .set('Geeksforneveropen', 3);let arr = [];myMap.forEach((values, keys) => { arr.push(keys); });console.log(arr); |
Output
[ 'GFG', 'Geeks', 'Geeksforneveropen' ]
