@polkadot/util/array/unzip.js

/**
 * @name arrayUnzip
 * @description Splits a single [K, V][] into [K[], V[]]
 */
export function arrayUnzip(entries) {
    const count = entries.length;
    const keys = new Array(count);
    const values = new Array(count);
    for (let i = 0; i < count; i++) {
        [keys[i], values[i]] = entries[i];
    }
    return [keys, values];
}