@reduxjs/toolkit 1.3.0-alpha.3

on Node.js Yarn

This alpha release alters the error-handling behavior of createAsyncThunk (again! 😁 )

Changes

createAsyncThunk Error Handling

In alpha.2, we tried having the thunk always re-throw caught errors. That didn't work out, because they always show up in the browser's console as unhandled exceptions.

Instead, the thunk now always returns a resolved promise containing the last action dispatched, which will be either the fulfilled action or the rejected action. We also export an unwrapAction utility that will either return action.payload if fulfilled or throw action.error if rejected, allowing the dispatching code to chain off the promise if desired:

import { unwrapResult } from '@reduxjs/toolkit'

// in the component
const onClick = () => {
  dispatch(fetchUserById(userId))
    .then(unwrapResult)
    .then(originalPromiseResult => {})
    .catch(serializedError => {})
}

Aborting Requests

Since createAsyncThunk accepts a promise callback, we have no way of knowing if or how the async logic can be canceled. However, we now provide a way for your logic to signal that cancellation needs to occur. An AbortController instance will be created for each request, and abort method will be attached to the returned promise that calls abortController.abort() and rejects the promise. The corresponding abortController.signal object will be passed in to your payload creator callback in the thunkAPI object as thunkAPI.signal, allowing your async logic to check if a cancellation has been requested.

Meta Field Names

The action.meta field in each action object previously looked like: {args, requestId}

The args field was renamed to arg to indicate it's only one value.

For the pending and fulfilled actions, action.meta is now: {arg, requestId}

The rejected action now includes details on whether the request was aborted, and
action.meta is now: {arg, requestId, aborted, abortReason}

Documentation

A first draft of API documentation for createAsyncThunk is now available:

createAsyncThunk draft API reference

Changes

v1.3.0-alpha.2...v1.3.0-alpha.3

See PR #352: Port ngrx/entity and add createAsyncThunk for the complete alpha changes.