typesafe objectEntries, objectFromEntries

objectEntries.ts

/**
 * Utility type to make complex types more readable in tooltips and error messages.
 */
type Prettify<T> = {
  [K in keyof T]: T[K];
} & {};

type ObjectEntry<T extends object> = Prettify<{ [K in keyof T]: [K, T[K]] }[keyof T]>;

type FromEntries<T extends Array<[PropertyKey, unknown]>> = {
  [K in T[number][0]]: Extract<T[number], [K, unknown]>[1]
};

/**
 * Returns an array of key-value pairs from an object.
 * @param object The object to convert to entries.
 * @returns An array of key-value pairs.
 */
export function objectEntries<T extends object>(
  object: T
) {
  return Object.entries(object) as Array<ObjectEntry<T>>;
}

/**
 * Creates an object from an array of key-value pairs.
 * @param entries An array of key-value pairs to convert to an object.
 * @returns An object created from the key-value pairs.
 */
export function objectFromEntries<T extends Array<[PropertyKey, unknown]>>(
  entries: T
) {
  return Object.fromEntries(entries) as Prettify<FromEntries<T>>;
}

// Example usage
const sampleObject = { alpha: 1, beta: "hello", gamma: true };
const entryArray = objectEntries(sampleObject);
// entryArray type: [string, string | number | boolean][]

const reconstructedObject = objectFromEntries(entryArray);
// reconstructedObject type: { alpha: number; beta: string; gamma: boolean }