49 lines
1.5 KiB
Plaintext
49 lines
1.5 KiB
Plaintext
import type {Subtract} from './subtract';
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import type {IsEqual} from './is-equal';
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type Recursive<T> = ReadonlyArray<Recursive<T>>;
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/**
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Creates a type that represents a multidimensional readonly array that of the given type and dimension.
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Use-cases:
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- Return a n-dimensional array from functions.
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- Declare a n-dimensional array by defining its dimensions rather than declaring `[]` repetitively.
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- Infer the dimensions of a n-dimensional array automatically from function arguments.
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- Avoid the need to know in advance the dimensions of a n-dimensional array allowing them to be dynamic.
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@example
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```
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import type {MultidimensionalReadonlyArray} from 'type-fest';
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function emptyMatrix<T extends number>(dimensions: T): MultidimensionalReadonlyArray<unknown, T> {
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const matrix: unknown[] = [];
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let subMatrix = matrix;
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for (let dimension = 1; dimension < dimensions; ++dimension) {
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console.log(`Initializing dimension #${dimension}`);
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subMatrix[0] = [];
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if (dimension < dimensions - 1) {
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subMatrix = subMatrix[0] as unknown[];
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} else {
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subMatrix[0] = 42;
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}
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}
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return matrix as MultidimensionalReadonlyArray<unknown, T>;
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}
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const matrix = emptyMatrix(3);
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const answer = matrix[0][0][0]; // 42
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```
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@category Array
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*/
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export type MultidimensionalReadonlyArray<Element, Dimensions extends number> = number extends Dimensions
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? Recursive<Element>
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: IsEqual<Dimensions, 0> extends true
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? Element
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: ReadonlyArray<MultidimensionalReadonlyArray<Element, Subtract<Dimensions, 1>>>;
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