How to Sort an Array in TypeScript ?

Array sorting is the process of arranging the elements within an array in a specified order, often either ascending or descending based on predetermined criteria.

Below are the approaches used to sort an array in typescript:

Method 1: Using sort method

The sort method is a built-in array method in TypeScript that sorts the elements of an array in place. It takes a compare function as an argument, allowing you to define custom sorting criteria.

Example: Sorting an array in ascending and descending order using the sort function.

Javascript

let numbers: number[] = [4, 2, 7, 1, 9];

// Ascending order
numbers.sort((a, b) => a - b);
console.log("Ascending: "+ numbers);

// Descending order
numbers.sort((a, b) => b - a);
console.log("Descending: "+ numbers);

Output:

Ascending: 1,2,4,7,9
Descending: 9,7,4,2,1 

Method 2: Spread Operator

This method involves creating a copy of the array using the spread operator (…) and then using array methods like sort. This approach keeps the original array unchanged and produces a new sorted array.

Example: Sorting an array in ascending and descending order using the sort with help of spread operator to keep the original array unchanged.

Javascript

let numbers: number[] = [4, 2, 7, 1, 9];

// Ascending order
let sortedAscending = [...numbers].sort((a, b) => a - b);
console.log("Ascending: " + sortedAscending);

// Descending order
let sortedDescending = [...numbers].sort((a, b) => b - a);
console.log("Descending: " + sortedDescending);

Output:

Ascending: 1,2,4,7,9
Descending: 9,7,4,2,1 

Method 3: Custom Sorting Function

We can define a custom sorting function based on our specific criteria and use it with the sort method. This method is useful when sorting complex data structures or when a custom sorting logic is required.

Example: Sorting the detail of person using defined custom sorting function based upon our requirement.

Javascript

let detail: { name: string; age: number }[] = [
  { name: "ABC", age: 30 },
  { name: "XYZ", age: 25 },
  { name: "MNP", age: 35 },
];

// Sort by age in ascending order
detail.sort((a, b) => a.age - b.age);
console.log(detail);

Output:

[
  { name: 'XYZ', age: 25 },
  { name: 'ABC', age: 30 },
  { name: 'MNP', age: 35 }
]