49 lines
1.5 KiB
Plaintext
49 lines
1.5 KiB
Plaintext
import type {Subtract} from './internal';
|
|
import type {IsEqual} from './is-equal';
|
|
|
|
type Recursive<T> = ReadonlyArray<Recursive<T>>;
|
|
|
|
/**
|
|
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.
|
|
|
|
@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
|
|
```
|
|
|
|
@category Array
|
|
*/
|
|
export type MultidimensionalReadonlyArray<Element, Dimensions extends number> = number extends Dimensions
|
|
? Recursive<Element>
|
|
: IsEqual<Dimensions, 0> extends true
|
|
? Element
|
|
: ReadonlyArray<MultidimensionalReadonlyArray<Element, Subtract<Dimensions, 1>>>;
|