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503337 (1) [Avatar] Offline
* enable reducer reloading (3.6.2)
* create new task (will get some Id, let's say 5)
* edit this task via ui (set new status)
* edit reducer

I would expect all actions to be replayed correctly, but 'edit task' action will not be applied. The issue appears because replaying 'create task' will add tasks objects with further increased ids (6), but 'edit' will still point to older one (5).

In order to fix this I moved getUniqueId to reducers/index.js, made it derive new id from existing tasks list and removed id from action payload. While this worked for me I wonder what is the correct way to handle such issues?

function uniqueId(tasks) {
  if (tasks && tasks.length !== 0) {
    const lastId = tasks.sort((a, b) => -[0].id
    return lastId + 1
  } else {
    return 1

const mockTasks = [
    id: 1,
    id: 2,

Called like this:

export default function tasks(state = { tasks: mockTasks }, action) {
  switch (action.type) {
    case 'CREATE_TASK': {
      const { title, description, status } = action.payload
      const id = uniqueId(state.tasks)

Marc Garreau (28) [Avatar] Offline
Nice catch, and well done for finding a solution! Our method for deriving IDs is definitely not well-suited for production; ultimately, its role is to mock behavior that a server should provide. I'll add a note to see if we add some clarifying language or code in the next round of updates. Thanks for the detailed write-up!