Function createTestOfflineEnvironment

packages/offline-transactions/tests/harness.ts:132–265

(
  options: TestOfflineEnvironmentOptions = {},
)

}

export function createTestOfflineEnvironment(
  options: TestOfflineEnvironmentOptions = {},
): {
  executor: ReturnType<typeof startOfflineExecutor>
  storage: FakeStorageAdapter
  collection: Collection<TestItem, string, {}>
  mutationFnName: string
  mutationCalls: Array<OfflineMutationFnParams & { attempt: number }>
  waitForLeader: () => Promise<void>
  leader: FakeLeaderElection
  serverState: Map<string, TestItem>
  applyMutations: (mutations: Array<PendingMutation<TestItem>>) => void
} {
  const mutationFnName = options.mutationFnName ?? `syncData`
  const storage = options.storage ?? new FakeStorageAdapter()
  const mutationCalls: Array<OfflineMutationFnParams & { attempt: number }> = []
  const attemptCounter = new Map<string, number>()

  const { collection, controller } = createDefaultCollection()
  const serverState = new Map<string, TestItem>()

  const applyMutations = (mutations: Array<PendingMutation<TestItem>>) => {
    controller.begin()

    for (const mutation of mutations) {
      switch (mutation.type) {
        case `insert`: {
          const value = mutation.modified
          serverState.set(value.id, value)
          controller.write({ type: `insert`, value })
          break
        }
        case `update`: {
          const value = mutation.modified
          serverState.set(value.id, value)
          controller.write({ type: `update`, value })
          break
        }
        case `delete`: {
          const original = mutation.original as TestItem | undefined
          const fallbackIdFromKey =
            (typeof mutation.key === `string` ? mutation.key : undefined) ??
            mutation.globalKey.split(`:`).pop()
          const id = original?.id ?? fallbackIdFromKey

          if (!id) {
            throw new Error(
              `Unable to determine id for delete mutation ${mutation.globalKey}`,
            )
          }

          const previousValue = serverState.get(id)
          serverState.delete(id)

          const emittedValue: TestItem = previousValue ?? {
            id,
            value: original?.value ?? ``,
            completed: original?.completed ?? false,