DefinitelyTyped/types/array.prototype.flat/auto.d.ts

// Adapted from https://github.com/microsoft/TypeScript/blob/master/lib/lib.es2019.array.d.ts

interface ReadonlyArray<T> {
    /**
     * Returns a new array with all sub-array elements concatenated into it recursively up to the
     * specified depth.
     *
     * @param depth The maximum recursion depth
     */
    flat<U>(
        this:
            | ReadonlyArray<U[][][][]>
            | ReadonlyArray<ReadonlyArray<U[][][]>>
            | ReadonlyArray<Array<ReadonlyArray<U[][]>>>
            | ReadonlyArray<Array<Array<ReadonlyArray<U[]>>>>
            | ReadonlyArray<Array<Array<Array<ReadonlyArray<U>>>>>
            | ReadonlyArray<ReadonlyArray<ReadonlyArray<U[][]>>>
            | ReadonlyArray<ReadonlyArray<Array<Array<ReadonlyArray<U>>>>>
            | ReadonlyArray<ReadonlyArray<Array<Array<ReadonlyArray<U>>>>>
            | ReadonlyArray<ReadonlyArray<Array<Array<ReadonlyArray<U>>>>>
            | ReadonlyArray<ReadonlyArray<Array<ReadonlyArray<U[]>>>>
            | ReadonlyArray<ReadonlyArray<Array<ReadonlyArray<U[]>>>>
            | ReadonlyArray<ReadonlyArray<ReadonlyArray<ReadonlyArray<U[]>>>>
            | ReadonlyArray<ReadonlyArray<ReadonlyArray<Array<ReadonlyArray<U>>>>>
            | ReadonlyArray<ReadonlyArray<ReadonlyArray<Array<ReadonlyArray<U>>>>>
            | ReadonlyArray<Array<ReadonlyArray<ReadonlyArray<ReadonlyArray<U>>>>>
            | ReadonlyArray<ReadonlyArray<ReadonlyArray<ReadonlyArray<ReadonlyArray<U>>>>>,
        depth: 4,
    ): U[];

    /**
     * Returns a new array with all sub-array elements concatenated into it recursively up to the
     * specified depth.
     *
     * @param depth The maximum recursion depth
     */
    flat<U>(
        this:
            | ReadonlyArray<U[][][]>
            | ReadonlyArray<Array<Array<ReadonlyArray<U>>>>
            | ReadonlyArray<Array<ReadonlyArray<U[]>>>
            | ReadonlyArray<ReadonlyArray<U[][]>>
            | ReadonlyArray<ReadonlyArray<ReadonlyArray<U[]>>>
            | ReadonlyArray<ReadonlyArray<Array<ReadonlyArray<U>>>>
            | ReadonlyArray<ReadonlyArray<Array<ReadonlyArray<U>>>>
            | ReadonlyArray<ReadonlyArray<ReadonlyArray<ReadonlyArray<U>>>>,
        depth: 3,
    ): U[];

    /**
     * Returns a new array with all sub-array elements concatenated into it recursively up to the
     * specified depth.
     *
     * @param depth The maximum recursion depth
     */
    flat<U>(
        this:
            | ReadonlyArray<U[][]>
            | ReadonlyArray<ReadonlyArray<U[]>>
            | ReadonlyArray<Array<ReadonlyArray<U>>>
            | ReadonlyArray<ReadonlyArray<ReadonlyArray<U>>>,
        depth: 2,
    ): U[];

    /**
     * Returns a new array with all sub-array elements concatenated into it recursively up to the
     * specified depth.
     *
     * @param depth The maximum recursion depth
     */
    flat<U>(this: ReadonlyArray<U[]> | ReadonlyArray<ReadonlyArray<U>>, depth?: 1): U[];

    /**
     * Returns a new array with all sub-array elements concatenated into it recursively up to the
     * specified depth.
     *
     * @param depth The maximum recursion depth
     */
    flat<U>(this: ReadonlyArray<U>, depth: 0): U[];

    /**
     * Returns a new array with all sub-array elements concatenated into it recursively up to the
     * specified depth. If no depth is provided, flat method defaults to the depth of 1.
     *
     * @param depth The maximum recursion depth
     */
    flat(depth?: number): any[];
}

interface Array<T> {
    /**
     * Returns a new array with all sub-array elements concatenated into it recursively up to the
     * specified depth.
     *
     * @param depth The maximum recursion depth
     */
    flat<U>(this: U[][][][][][][][], depth: 7): U[];

    /**
     * Returns a new array with all sub-array elements concatenated into it recursively up to the
     * specified depth.
     *
     * @param depth The maximum recursion depth
     */
    flat<U>(this: U[][][][][][][], depth: 6): U[];

    /**
     * Returns a new array with all sub-array elements concatenated into it recursively up to the
     * specified depth.
     *
     * @param depth The maximum recursion depth
     */
    flat<U>(this: U[][][][][][], depth: 5): U[];

    /**
     * Returns a new array with all sub-array elements concatenated into it recursively up to the
     * specified depth.
     *
     * @param depth The maximum recursion depth
     */
    flat<U>(this: U[][][][][], depth: 4): U[];

    /**
     * Returns a new array with all sub-array elements concatenated into it recursively up to the
     * specified depth.
     *
     * @param depth The maximum recursion depth
     */
    flat<U>(this: U[][][][], depth: 3): U[];

    /**
     * Returns a new array with all sub-array elements concatenated into it recursively up to the
     * specified depth.
     *
     * @param depth The maximum recursion depth
     */
    flat<U>(this: U[][][], depth: 2): U[];

    /**
     * Returns a new array with all sub-array elements concatenated into it recursively up to the
     * specified depth.
     *
     * @param depth The maximum recursion depth
     */
    flat<U>(this: U[][], depth?: 1): U[];

    /**
     * Returns a new array with all sub-array elements concatenated into it recursively up to the
     * specified depth.
     *
     * @param depth The maximum recursion depth
     */
    flat<U>(this: U[], depth: 0): U[];

    /**
     * Returns a new array with all sub-array elements concatenated into it recursively up to the
     * specified depth. If no depth is provided, flat method defaults to the depth of 1.
     *
     * @param depth The maximum recursion depth
     */
    flat(depth?: number): any[];
}