Type Alias MultidimensionalReadonlyArray<Element, Dimensions>

MultidimensionalReadonlyArray: number extends Dimensions
    ? Recursive<Element>
    : IsEqual<Dimensions, 0> extends true
        ? Element
        : ReadonlyArray<
            MultidimensionalReadonlyArray<Element, Subtract<Dimensions, 1>>,
        >

Creates a type that represents a multidimensional readonly array that of the given type and dimension.

Use-cases:

  • Return a n-dimensional array from functions.
  • Declare a n-dimensional array by defining its dimensions rather than declaring [] repetitively.
  • Infer the dimensions of a n-dimensional array automatically from function arguments.
  • Avoid the need to know in advance the dimensions of a n-dimensional array allowing them to be dynamic.

Type Parameters

  • Element
  • Dimensions extends number

Example

import type {MultidimensionalReadonlyArray} from 'type-fest';

function emptyMatrix<T extends number>(dimensions: T): MultidimensionalReadonlyArray<unknown, T> {
	const matrix: unknown[] = [];

	let subMatrix = matrix;
	for (let dimension = 1; dimension < dimensions; ++dimension) {
		console.log(`Initializing dimension #${dimension}`);

		subMatrix[0] = [];
		if (dimension < dimensions - 1) {
			subMatrix = subMatrix[0] as unknown[];
		} else {
			subMatrix[0] = 42;
		}
	}

	return matrix as MultidimensionalReadonlyArray<unknown, T>;
}

const matrix = emptyMatrix(3);

const answer = matrix[0][0][0]; // 42

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