How to declare an array in TypeScript



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In TypeScript, you can declare an array using the following syntax:

typescript
// Explicitly declare the type of elements in the array
let myArray: number[] = [1, 2, 3, 4, 5];

// Another way to declare an array with the Array<elementType> syntax
let anotherArray: Array<string> = ["apple", "banana", "orange"];

// You can also declare an array without initializing it
let emptyArray: number[] = [];

// Initialize an array later
emptyArray = [1, 2, 3];

// Arrays can contain different types of elements
let mixedArray: (string | number)[] = ["apple", 1, "banana", 2];

// TypeScript allows you to use the Array type with union types
let unionArray: Array<string | number> = ["apple", 1, "banana", 2];

In the examples above:

  • myArray is an array of numbers.
  • anotherArray is an array of strings.
  • emptyArray is initially declared without any elements and later initialized with numbers.
  • mixedArray is an array that can hold either strings or numbers.
  • unionArray is another way to declare an array with a union type.

Remember that TypeScript provides static typing, so declaring the type of elements in the array allows the compiler to catch potential type errors during development. If you try to assign an element of the wrong type to the array, TypeScript will generate a compilation error.

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