immutable-flow.js

// @flow
import * as I from 'immutable'

export function defineRecord<T: Object>(
	name: string,
	spec: T
): (init: $Shape<T>) => Record<T> {
	return I.Record(spec, name)
}

export type Record<T: Object> = RecordMethods<T> & T;

declare class RecordMethods<T: Object> {
  get<A>(key: $Keys<T>): A;
  set<A>(key: $Keys<T>, value: A): Record<T>;
  update<A>(key: $Keys<T>, updater: (value: A) => A): Record<T>;
  updateIn<A>(path: Iterable<any>, notSetOrUpdater: A | (value: A) => A, updater?: (value: A) => A): Record<T>;
  setIn<A>(path: Iterable<any>, value: A): Record<T>;
  deleteIn<A>(path: Iterable<any>): Record<T>;
  merge(values: $Shape<T>): Record<T>;
  inspect(): string;
  toObject(): T;
  // add more as needed
}

type X = {
	id: number,
	name: string,
}

type XRecord = Record<X>

const Thing = defineRecord('Thing', ({id: 0, name: ''}: X))

const x: XRecord = Thing({name: 'akameco', id: 0})
x.get('name')
x.set('name', 'hoge')
x.setIn('name', 'hoge')