TypeScript Array concat()
Syntax & Examples

Array.concat() method

The concat() method in TypeScript is used to merge two or more arrays. This method does not change the existing arrays but instead returns a new array containing the values of the joined arrays.

Syntax of Array.concat()

There are 2 variations for the syntax of Array.concat() method. They are:

1.
concat(...items: ConcatArray<T>[]): T[]

Parameters

ParameterOptional/RequiredDescription
itemsoptionalArrays and/or values to concatenate into a new array.

This method combines multiple arrays or values into a new array.

Returns value of type Array.

2.
concat(...items: (T | ConcatArray<T>)[]): T[]

Parameters

ParameterOptional/RequiredDescription
itemsoptionalArrays and/or values to concatenate into a new array.

This method combines multiple arrays or values into a new array.

Returns value of type Array.


✐ Examples

1 Using concat() method with multiple arrays

In TypeScript, you can use the concat() method to merge multiple arrays into a new array.

For example,

  1. Define two arrays arr1 and arr2 with some initial values.
  2. Use the concat() method to merge arr1 and arr2 into a new array.
  3. Store the result in the variable mergedArray.
  4. Log mergedArray to the console using the console.log() method.

TypeScript Program

const arr1 = [1, 2, 3];
const arr2 = [4, 5, 6];
const mergedArray = arr1.concat(arr2);
console.log(mergedArray);

Output

[1, 2, 3, 4, 5, 6]

2 Using concat() method with multiple values

In TypeScript, you can use the concat() method to concatenate multiple values to an array.

For example,

  1. Define an array arr with some initial values.
  2. Use the concat() method to concatenate additional values to arr.
  3. Store the result in the variable newArray.
  4. Log newArray to the console using the console.log() method.

TypeScript Program

const arr = [1, 2, 3];
const newArray = arr.concat(4, 5, 6);
console.log(newArray);

Output

[1, 2, 3, 4, 5, 6]

3 Using concat() method with arrays and values

In TypeScript, you can use the concat() method to concatenate arrays and values together.

For example,

  1. Define two arrays arr1 and arr2 with some initial values.
  2. Use the concat() method to concatenate arr1, arr2, and additional values together.
  3. Store the result in the variable resultArray.
  4. Log resultArray to the console using the console.log() method.

TypeScript Program

const arr1 = [1, 2];
const arr2 = [5, 6];
const resultArray = arr1.concat(3, 4, arr2);
console.log(resultArray);

Output

[1, 2, 3, 4, 5, 6]

Summary

In this TypeScript tutorial, we learned about concat() method of Array: the syntax and few working examples with output and detailed explanation for each example.