Function applyMutations

packages/offline-transactions/tests/harness.ts:153–204

(mutations: Array<PendingMutation<TestItem>>)

  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,
            updatedAt: original?.updatedAt ?? new Date(),
          }

          controller.write({
            type: `delete`,
            value: emittedValue,
          })
          break
        }
      }
    }

    controller.commit()
    controller.markReady()
  }

  const defaultMutation: TestMutationFn = (params) => {
    const mutations = params.transaction.mutations as Array<