How to useMap.entries() and sort() Method in Javascript
One way to achieve this goal is to use the in-built sort() function available in JavaScript on the multi-dimensional Array created with the help of the array destructuring of the object generated by the Map.entries() method.
Syntax:
[...map1.entries()]
# this will generate a multi-dimensional array
# out of the key-value pairs stored in the map
Example 1: In this example, we are sorting the map by the increasing values of keys.
// Initializing and inserting values into Map
let map1 = new Map([
[4, 2],
[2, 3],
]);
// Inserting new element into map using set() method
map1.set(3, 10);
console.log("Our map :");
console.log(map1);
// Adding the sorting logic
map1 = new Map([...map1.entries()].sort());
// Separately printing only keys
for (let [key, value] of map1) {
console.log(key, " ");
}
Output
Our map :
Map(3) { 4 => 2, 2 => 3, 3 => 10 }
2
3
4
Example 2: In this example, we are sorting the map by the decreasing values of keys.
let map1 = new Map([
[4, 2],
[2, 3],
]);
// Inserting new element into map using set() method
map1.set(3, 10);
console.log("Our map :");
console.log(map1);
// Adding the custom sorting logic to sort
// by decreasing values of keys
map1 = new Map([...map1.entries()].sort((a, b) => b[0] - a[0]));
// Separately printing only keys
for (let [key, value] of map1) {
console.log(key, " ");
}
Output
Our map :
Map(3) { 4 => 2, 2 => 3, 3 => 10 }
4
3
2
How to sort a map in JavaScript ?
We will see how to sort the Map according to the value of the keys.
Map in JavaScript is a special kind of object that stores elements in terms of [key, value] pair. The map can store both primitive as well as objects. When iterating over the map object, it returns the [key, value] pair in the same order as inserted.
Below are the following approaches:
Table of Content
- Using Map.entries() and sort() Method
- Using Array.from() and sort() Method