Just playing with how a native Array.prototype.mapKey would look.

Array.prototype.mapKey.js

/**
 *
 * @name: Array.prototype.mapKey
 * @author: @moekhalil (GitHub)
 *
 * @description: A prototype of a native Array.prototype.mapKey that
 *               would allow users to map over an array of objects
 *               and return the value of a specific key or nested key
 *
 * @param prop {string | string[] | function}
 * @returns {any[]}
 */

Array.prototype.mapKey = function (prop) {
  if (typeof prop === 'string') {
    return this.map((item) => item[prop]);
  }

  if (Array.isArray(prop)) {
    if (prop.length === 1) {
      return this.map((item) => item[prop[0]]);
    }

    return this.map((item) =>
      prop.reduce((o, key) => (o ? o[key] : void 0), item)
    );
  }

  if (typeof prop === 'function') {
    return this.map(prop);
  }

  if (typeof prop === 'undefined') {
    throw new Error(
      'mapKey requires a property name, array of property names, or function'
    );
  }
};