Array Type in TypeScript

• In TypeScript, you can declare an array type using the syntax type[] or Array<type>, where type is the type of the elements in the array.

Here are a few examples:

    // Array of numbers

    let numbers: number[] = [1, 2, 3, 4, 5];

    let moreNumbers: Array<number> = [6, 7, 8, 9, 10];

    // Array of strings

    let strings: string[] = ["apple", "banana", "cherry"];

    let moreStrings: Array<string> = ["date", "elderberry", "fig"];

    // Array of booleans

    let booleans: boolean[] = [true, false, true];

    let moreBooleans: Array<boolean> = [false, true, false];

    // Array of any

    let anyValue: any[] = [1, "2", true, [3, "2"], { name: "john" }]

    let moreAnyValue: Array<any> = [1, "2", true, [3, "2"], { name: "john" }]

• You can also use type assertions to specify the type of an array without initializing it:

    let emptyArray: number[] = [];

    emptyArray.push(1);

    emptyArray.push(2);

    emptyArray.push(3);

    // Type assertion

    let stringArray: string[] = [] as string[];

    stringArray.push("hello");

    stringArray.push("world");

    console.log(emptyArray);

    console.log(stringArray);

[ 1, 2, 3 ]

[ 'hello', 'world' ]

• TypeScript also supports readonly arrays, which are arrays whose elements cannot be modified once they are assigned:

    let readonlyArray: readonly number[] = [1, 2, 3];

    readonlyArray[0] = 4; // Error: Index signature in type 'readonly number[]' only permits reading

    readonlyArray.push(4); // Error: Property 'push' does not exist on type 'readonly number[]'

• In addition to these basic array types, TypeScript provides various utility types and methods to work with arrays, such as Partial<T>, ReadonlyArray<T>, map(), filter(), etc. These utilities can be helpful when working with arrays in TypeScript.