robonen
96f4cba4a8
- Add array/async/etc. modules and type tests; migrate to eslint flat config and composite tsconfig (vitest typecheck enabled). - Fix PubSub.emit to snapshot listeners before iterating (stable EventEmitter semantics; avoids invoking listeners added during the same emit).
30 lines
988 B
TypeScript
30 lines
988 B
TypeScript
import { describe, expect, it } from 'vitest';
|
|
import { last } from '.';
|
|
|
|
describe('last', () => {
|
|
it('return the last element of a non-empty array', () => {
|
|
expect(last([1, 2, 3, 4, 5])).toBe(5);
|
|
expect(last(['a', 'b', 'c'])).toBe('c');
|
|
});
|
|
|
|
it('return undefined if the array is empty and no default value is provided', () => {
|
|
expect(last([])).toBeUndefined();
|
|
});
|
|
|
|
it('return the default value for an empty array with a default value', () => {
|
|
expect(last([], 42)).toBe(42);
|
|
expect(last([], 'default')).toBe('default');
|
|
});
|
|
|
|
it('return the first element even if a default value is provided', () => {
|
|
expect(last([1, 2, 3], 42)).toBe(3);
|
|
expect(last(['a', 'b', 'c'], 'default')).toBe('c');
|
|
});
|
|
|
|
it('preserve a present null/undefined/falsy last element (not the default)', () => {
|
|
expect(last([1, null as number | null], 42)).toBeNull();
|
|
expect(last([1, undefined], 42)).toBeUndefined();
|
|
expect(last([0], 99)).toBe(0);
|
|
});
|
|
});
|