Object array functions

This package proposes array methods (map, filter, find, reduce) for objects, in Typescript.

map

This is equivalent to Array.map. It maps a key and value to the new value. The prototype is map(func: (k: string, v: any, o: Object) => any): Object.

Usage example:

import { asMap } from 'object-array-methods';

const before = { a: 1, b: 4 };
const after = asMap(before).map((k, v) => v + v);

console.log(after);

// Expected result: { a: 2, b: 8 }

filter

This is equivalent to Array.filter. It filters an object. The prototype is filter(func: (k: string, v: any, o: Object) => boolean): Object.

Usage example:

import { asMap } from 'object-array-methods';

const before = { a: 1, b: 4 };
const after = asMap(before).filter((k, v) => v > 2);

console.log(after);

// Expected result: { b: 4 }

find

This is equivalent to Array.find. It finds using a predicate in an object, and returns the key of the first entry that made the predicate true, and undefined if none of the entry made the predicate. The prototype is find(func: (k: string, v: any, o: Object) => boolean): string | undefined.

Usage example:

import { asMap } from 'object-array-methods';

const before = { a: 1, b: 4 };
const found = asMap(before).find((k, v) => v > 2);

console.log(found);

// Expected result: b

reduce

This is equivalent to Array.reduce. It reduces the object into a (generic) value. The prototype is reduce<T>(func: (acc: T, k: string, v: any, o: Object) => T, initialValue: T): T.

Usage example:

import { asMap } from 'object-array-methods';

const before = { a: 1, b: 4 };
const result = asMap(before).reduce((acc, k, v) => acc + v, 0);

console.log(result);

// Expected result: 5