frontend-svelte/src/shared/lib/utils/splitArray/splitArray.ts

/**
 * Splits an array into two arrays based on a callback function.
 * @param array The array to split.
 * @param callback The callback function to determine which array to push each item to.
 * @returns - An array containing two arrays, the first array contains items that passed the callback, the second array contains items that failed the callback.
 */
export function splitArray<T>(array: T[], callback: (item: T) => boolean) {
    return array.reduce<[T[], T[]]>(
        ([pass, fail], item) => (
            callback(item) ? pass.push(item) : fail.push(item), [pass, fail]
        ),
        [[], []],
    );
}