JamieMason/syncpack

/**
 * Convert an array of objects to an object, where each member of the array has
 * a unique value for the given key. The new object keys each object by its
 * value for the given key.
 */

export function keyBy<A extends any[]>(key: string, array: A): Record<string, A[number]> {
  return array.reduce((objectsByKeyValue, obj) => {
    const value = obj[key];
    objectsByKeyValue[value] = obj;
    return objectsByKeyValue;
  }, {});
}