ts-prime/src/entries.test.ts

A utility library for JavaScript and Typescript.

import { ensureType } from './ensureType';
import { fromEntries, entries } from './entries';
import { pipe } from './pipe';

test('should return pairs', () => {
  const start = { a: 1, b: 2, c: 3 };
  const actual = entries({ a: 1, b: 2, c: 3 });
  ensureType<ReadonlyArray<['a' | 'b' | 'c', number]>>(actual);
  expect(fromEntries(actual)).toEqual(start);
  ensureType<Record<'a' | 'b' | 'c', number>>(fromEntries(actual));
  expect(actual).toEqual([
    ['a', 1],
    ['b', 2],
    ['c', 3],
  ]);
});



test('should return pairs', () => {
  const start = { a: 1, b: 2, c: 3 };
  const actual = entries({ a: 1, b: 2, c: 3 });
  const result = pipe(start, entries(), fromEntries())
  ensureType<{ a: number, b: number, c: number }>(result)
  ensureType<ReadonlyArray<['a' | 'b' | 'c', number]>>(actual);
  expect(fromEntries(actual)).toEqual(start);
  ensureType<Record<'a' | 'b' | 'c', number>>(fromEntries(actual));
  expect(actual).toEqual([
    ['a', 1],
    ['b', 2],
    ['c', 3],
  ]);
});



test('should return pairs', () => {
  const start = ["a", "b", "c"].map((v, i) => [v, i] as const);
  const result = fromEntries(start)
  ensureType<{ [k: string]: number }>(result)

  expect(result).toEqual({
    a: 0, b: 1, c: 2
  });
});