indexed-utils.ts

	export interface StringBasedIndexedEntry {
	id: string;
}

export interface NumberBasedIndexedEntry {
	id: number;
}

type AnyIndexedEntry = StringBasedIndexedEntry | NumberBasedIndexedEntry;

export type Indexed<T> = T extends StringBasedIndexedEntry
	? {
			[key: string]: T;
	  } // tslint:disable-line: indent
	: {
			[key: number]: T;
	  }; // tslint:disable-line: indent

export const arrayToIndexed = <T extends AnyIndexedEntry>(a: T[]): Indexed<T> =>
	a.reduce((acc, val) => {
		return { ...acc, [val.id]: val };
	}, {} as Indexed<T>);

export const filterIndexed = <T extends AnyIndexedEntry>(
	predicateFn: (entry: T) => boolean,
	indexed: Indexed<T>
): Indexed<T> => arrayToIndexed(Object.values<T>(indexed).filter(predicateFn));