TypeScript Array concat()

In this chapter, we will explore the concat() method for arrays in TypeScript. This method is a built-in function that helps in merging two or more arrays into a single array. Understanding how to use concat() is useful for combining arrays and managing collections of data.

Table of Contents

1. Definition
2. Syntax
3. Examples
4. Conclusion

1. Definition

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

2. Syntax

array.concat(value1, value2, ..., valueN);

Parameters

• value1, value2, ..., valueN: Arrays and/or values to concatenate into a new array.

Return Value

The method returns a new array instance containing the concatenated values.

3. Examples

Let's look at some examples to understand how concat() works in TypeScript.

Example 1: Basic Usage

In this example, we concatenate two arrays into a new array.

let array1: number[] = [1, 2, 3];
let array2: number[] = [4, 5, 6];
let result = array1.concat(array2);
console.log(result); // Output: [1, 2, 3, 4, 5, 6]

Example 2: Concatenating Multiple Arrays

In this example, we concatenate multiple arrays into a new array.

let array1: number[] = [1, 2, 3];
let array2: number[] = [4, 5, 6];
let array3: number[] = [7, 8, 9];
let result = array1.concat(array2, array3);
console.log(result); // Output: [1, 2, 3, 4, 5, 6, 7, 8, 9]

Example 3: Concatenating Arrays and Values

In this example, we concatenate arrays and individual values into a new array.

let array1: number[] = [1, 2, 3];
let result = array1.concat(4, 5, [6, 7]);
console.log(result); // Output: [1, 2, 3, 4, 5, 6, 7]

Example 4: Concatenating Strings

In this example, we concatenate arrays of strings into a new array.

let array1: string[] = ["Hello"];
let array2: string[] = ["TypeScript", "World"];
let result = array1.concat(array2);
console.log(result); // Output: ["Hello", "TypeScript", "World"]

Example 5: Nested Arrays

In this example, we concatenate nested arrays. Note that concat() does not flatten nested arrays.

let array1: number[] = [1, 2, 3];
let array2: number[][] = [[4, 5], [6, 7]];
let result = array1.concat(array2);
console.log(result); // Output: [1, 2, 3, [4, 5], [6, 7]]

4. Conclusion

In this chapter, we explored the concat() method for arrays in TypeScript, which is used to merge two or more arrays into a single array. We covered its definition, syntax, parameters, return value, and provided several examples to demonstrate its usage. Understanding how to use concat() effectively can help in various array manipulation tasks in TypeScript, especially when combining multiple arrays and managing collections of data.