svelte-i18n/test/runtime/includes/loaderQueue.test.ts

import {
  hasLocaleQueue,
  flush,
  registerLocaleLoader,
  resetQueues,
} from '../../../src/runtime/includes/loaderQueue'
import { getMessageFromDictionary } from '../../../src/runtime/stores/dictionary'

beforeEach(() => {
  resetQueues()
})

const loader = (content: any) => () => new Promise(res => res(content))

test('registers a locale loader', () => {
  expect(hasLocaleQueue('pt-BR')).toBe(false)
  registerLocaleLoader('pt-BR', loader({ message: 'Mensagem' }))
  expect(hasLocaleQueue('pt-BR')).toBe(true)
})

test('checks if exist queues of locale and its fallbacks', () => {
  registerLocaleLoader('en', loader({ field: 'Name' }))
  expect(hasLocaleQueue('en-US')).toBe(true)
})

test("does nothing if there's no queue for a locale", () => {
  expect(flush('foo')).toBe(undefined)
})

test('flushes the queue of a locale and its fallbacks and merge the result with the dictionary', async () => {
  registerLocaleLoader('en', loader({ field: 'Name' }))
  registerLocaleLoader('en-US', loader({ field_2: 'Lastname' }))

  await flush('en-US')

  expect(getMessageFromDictionary('en', 'field')).toBe('Name')
  expect(getMessageFromDictionary('en-US', 'field_2')).toBe('Lastname')

  expect(hasLocaleQueue('en')).toBe(false)
  expect(hasLocaleQueue('en-US')).toBe(false)
})

test('consecutive flushes return the same promise', async () => {
  registerLocaleLoader('en', async () => ({}))

  const flushA = flush('en')
  const flushB = flush('en')
  const flushC = flush('en')

  expect(flushB).toStrictEqual(flushA)
  expect(flushC).toStrictEqual(flushA)
})

test('waits for loaders added while already flushing', async () => {
  registerLocaleLoader(
    'en',
    () => new Promise(res => setTimeout(() => res({ foo: 'foo' }), 300))
  )

  const flushPromise = flush('en')

  registerLocaleLoader(
    'en',
    () => new Promise(res => setTimeout(() => res({ bar: 'bar' })))
  )

  await flushPromise

  expect(getMessageFromDictionary('en', 'foo')).toBe('foo')
  expect(getMessageFromDictionary('en', 'bar')).toBe('bar')
})