import { describe, expect, it } from 'vitest'
import { first, isNonEmpty } from '../../../src/utils/array-helpers.js'
describe('Array Helpers', () => {
describe('first', () => {
it.each([
[[1, 2, 3], 1],
[['a'], 'a'],
[[{ id: 1 }], { id: 1 }]
])('first(%j) -> %p', (arr, expected) => {
expect(first(arr)).toEqual(expected)
})
it('throws on empty array', () => {
expect(() => first([])).toThrow('Array is empty')
})
it('includes context in error message', () => {
expect(() => first([], 'Getting widget')).toThrow('Getting widget: Array is empty')
})
})
describe('isNonEmpty', () => {
it.each([
[[1], true],
[[1, 2, 3], true],
[[], false]
])('isNonEmpty(%j) -> %s', (arr, expected) => {
expect(isNonEmpty(arr)).toBe(expected)
})
it('narrows type when true', () => {
const arr: number[] = [1, 2, 3]
if (isNonEmpty(arr)) {
// TypeScript knows arr[0] is number, not number | undefined
const first: number = arr[0]
expect(first).toBe(1)
}
})
})
})
