identity function in createAction only handles the first parameter

The createAction function returns an action creator with the signature function(...args). However, if you do not pass an actionCreator method to the createAction function, then the “identity” function is used.

The identity function is this: (t) => t, which does not do an argument spread and, since it is called with function.apply, it only handles the first argument passed in to the action creator, even though the action creator is designed around supporting n arguments.

[calvinnwq]

I personally do (arg1, arg2) => ({ arg1, arg2 }) if i have arguments to pass. Even if it were a single argument, I’d still do (arg1) => ({ arg1 }) just to keep it consistent and make it more readable in the reducers, especially in larger apps.

e.g.

// action
const actions = {
  entry: {
    add: createAction('ADD_ENTRY', (entry) => ({ entry })),
  }
};
// reducer
[actions.entry.add]: (state, payload) => ({
    ...state,
    entry: [
      ...state.entry,
      payload.entry,
    ],
  }),

Since I pass my own payloadCreator all the time, I don’t encounter the problem as discussed here.

Also, since JavaScript does not have support for named parameters like in some other languages e.g. python where you can specify functionName(arg1=1, arg2=2), you can pass an object literal as your only argument.

const addEntry = createAction('ADD_ENTRY'),
const entry = { name: 'entry name' };
addEntry({ entry }); // same as addEntry({ entry: entry });

this then will work with redux-actions with the default identity

---

I don’t really agree with passing multiple arguments as an array as payload, since you’d have to again assume the order of the arguments passed which makes code less readable and less flexible.

But, not passing all arguments is bad as well as it restricts by default, so I’d say the solution mentioned by @yangmillstheory above is sufficient.

[yangmillstheory]

Yeah, I’m wondering what the maintainers or the upvoters think. ping @timche @hale @calvinnwq.

I didn’t mean to shoot your point down; after discussion what you propose seems reasonable! I do think that in the case multiple arguments, someone might be passing a custom action creator. But this would handle the case of having to pass

(...args) => (args.length === 1 ? args[0] : args;)

👍