How to Sort a Map by Values in JavaScript

How to Sort a Map by Values in JavaScript ?

Answer

To sort a map by values in JavaScript, you can convert the map to an array of key-value pairs, sort the array by values, and then convert it back to a map. This method provides a straightforward way to ensure the map is sorted by values.

✐ Examples

1 Sorting a Map by Values Using Array Conversion

We can sort a map by values in JavaScript by converting the map to an array of key-value pairs, sorting the array by values, and then converting it back to a map.

For example,

We start by declaring and initializing a map named myMap with some key-value pairs. In this example, the map has string keys and integer values.
We convert the map to an array of key-value pairs using the Array.from method.
We sort the array by values using the sort method.
We create a new map from the sorted array using the Map constructor.
We print the sorted map to the console using the console.log function to verify the sorting.

JavaScript Program

const myMap = new Map([
    ['apple', 3],
    ['banana', 1],
    ['cherry', 2]
]);

// Convert the map to an array of key-value pairs
const sortedArray = Array.from(myMap).sort((a, b) => a[1] - b[1]);

// Create a new map from the sorted array
const sortedMap = new Map(sortedArray);

// Print the sorted map
console.log('Sorted Map by Values:', Array.from(sortedMap));

Output

Sorted Map by Values: [['banana', 1], ['cherry', 2], ['apple', 3]]

2 Sorting a Map by Values in Descending Order

We can sort a map by values in descending order in JavaScript by converting the map to an array of key-value pairs, sorting the array by values in descending order, and then converting it back to a map.

For example,

We start by declaring and initializing a map named myMap with some key-value pairs. In this example, the map has string keys and integer values.
We convert the map to an array of key-value pairs using the Array.from method.
We sort the array by values in descending order using the sort method with a custom comparator.
We create a new map from the sorted array using the Map constructor.
We print the sorted map to the console using the console.log function to verify the sorting.

JavaScript Program

const myMap = new Map([
    ['apple', 3],
    ['banana', 1],
    ['cherry', 2]
]);

// Convert the map to an array of key-value pairs
const sortedArray = Array.from(myMap).sort((a, b) => b[1] - a[1]);

// Create a new map from the sorted array
const sortedMap = new Map(sortedArray);

// Print the sorted map
console.log('Sorted Map by Values (Descending):', Array.from(sortedMap));

Output

Sorted Map by Values (Descending): [['apple', 3], ['cherry', 2], ['banana', 1]]

3 Sorting a Map with Numeric Keys by Values

We can sort a map with numeric keys by values in JavaScript by converting the map to an array of key-value pairs, sorting the array by values, and then converting it back to a map.

For example,

We start by declaring and initializing a map named myMap with some key-value pairs. In this example, the map has numeric keys and string values.
We convert the map to an array of key-value pairs using the Array.from method.
We sort the array by values using the sort method.
We create a new map from the sorted array using the Map constructor.
We print the sorted map to the console using the console.log function to verify the sorting.

JavaScript Program

const myMap = new Map([
    [3, 'three'],
    [1, 'one'],
    [2, 'two']
]);

// Convert the map to an array of key-value pairs
const sortedArray = Array.from(myMap).sort((a, b) => a[1].localeCompare(b[1]));

// Create a new map from the sorted array
const sortedMap = new Map(sortedArray);

// Print the sorted map
console.log('Sorted Map by Values:', Array.from(sortedMap));

Output

Sorted Map by Values: [[1, 'one'], [2, 'two'], [3, 'three']]

Summary

In this tutorial, we learned How to Sort a Map by Values in JavaScript language with well detailed examples.

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