fromPairs

1/**
2 * Converts an array of [key, value] pairs into an object.
3 *
4 * @param pairs - An array of [key, value] tuples.
5 * @returns An object constructed from the given pairs.
6 */
7export function fromPairs<T>(pairs: [string, T][]): Record<string, T> {
8  return pairs.reduce((acc, [key, value]) => {
9    acc[key] = value;
10    return acc;
11  }, {} as Record<string, T>);
12}

1test('fromPairs - converts pairs to object', () => {
2  const input: [string, number][] = [['a', 1], ['b', 2]];
3  expect(fromPairs(input)).toEqual({ a: 1, b: 2 });
4});
5
6test('fromPairs - handles empty input', () => {
7  expect(fromPairs([])).toEqual({});
8});
9
10test('fromPairs - overwrites duplicate keys with last value', () => {
11  const input: [string, string][] = [['a', 'x'], ['a', 'y']];
12  expect(fromPairs(input)).toEqual({ a: 'y' });
13});
14
15test('fromPairs - works with mixed value types', () => {
16  const input: [string, any][] = [['a', 1], ['b', 'hello'], ['c', true]];
17  expect(fromPairs(input)).toEqual({ a: 1, b: 'hello', c: true });
18});
19
20test('fromPairs - original array is not mutated', () => {
21  const input: [string, number][] = [['a', 1], ['b', 2]];
22  const clone = [...input];
23  fromPairs(input);
24  expect(input).toEqual(clone);
25});