import type { AnyAction, Reducer } from 'redux'
import { createNextState } from '.'
import type {
ActionCreatorWithoutPayload,
PayloadAction,
PayloadActionCreator,
PrepareAction,
_ActionCreatorWithPreparedPayload,
} from './createAction'
import { createAction } from './createAction'
import type {
CaseReducer,
CaseReducers,
ReducerWithInitialState,
} from './createReducer'
import { createReducer, NotFunction } from './createReducer'
import type { ActionReducerMapBuilder } from './mapBuilders'
import { executeReducerBuilderCallback } from './mapBuilders'
import type { NoInfer } from './tsHelpers'
import { freezeDraftable } from './utils'
let hasWarnedAboutObjectNotation = false
/**
* An action creator attached to a slice.
*
* @deprecated please use PayloadActionCreator directly
*
* @public
*/
export type SliceActionCreator<P> = PayloadActionCreator<P>
/**
* The return value of `createSlice`
*
* @public
*/
export interface Slice<
State = any,
CaseReducers extends SliceCaseReducers<State> = SliceCaseReducers<State>,
Name extends string = string
> {
/**
* The slice name.
*/
name: Name
/**
* The slice's reducer.
*/
reducer: Reducer<State>
/**
* Action creators for the types of actions that are handled by the slice
* reducer.
*/
actions: CaseReducerActions<CaseReducers, Name>
/**
* The individual case reducer functions that were passed in the `reducers` parameter.
* This enables reuse and testing if they were defined inline when calling `createSlice`.
*/
caseReducers: SliceDefinedCaseReducers<CaseReducers>
/**
* Provides access to the initial state value given to the slice.
* If a lazy state initializer was provided, it will be called and a fresh value returned.
*/
getInitialState: () => State
}
/**
* Options for `createSlice()`.
*
* @public
*/
export interface CreateSliceOptions<
State = any,
CR extends SliceCaseReducers<State> = SliceCaseReducers<State>,
Name extends string = string
> {
/**
* The slice's name. Used to namespace the generated action types.
*/
name: Name
/**
* The initial state that should be used when the reducer is called the first time. This may also be a "lazy initializer" function, which should return an initial state value when called. This will be used whenever the reducer is called with `undefined` as its state value, and is primarily useful for cases like reading initial state from `localStorage`.
*/
initialState: State | (() => State)
/**
* A mapping from action types to action-type-specific *case reducer*
* functions. For every action type, a matching action creator will be
* generated using `createAction()`.
*/
reducers: ValidateSliceCaseReducers<State, CR>
/**
* A callback that receives a *builder* object to define
* case reducers via calls to `builder.addCase(actionCreatorOrType, reducer)`.
*
* Alternatively, a mapping from action types to action-type-specific *case reducer*
* functions. These reducers should have existing action types used
* as the keys, and action creators will _not_ be generated.
*
* @example
```ts
import { createAction, createSlice, Action, AnyAction } from '@reduxjs/toolkit'
const incrementBy = createAction<number>('incrementBy')
const decrement = createAction('decrement')
interface RejectedAction extends Action {
error: Error
}
function isRejectedAction(action: AnyAction): action is RejectedAction {
return action.type.endsWith('rejected')
}
createSlice({
name: 'counter',
initialState: 0,
reducers: {},
extraReducers: builder => {
builder
.addCase(incrementBy, (state, action) => {
// action is inferred correctly here if using TS
})
// You can chain calls, or have separate `builder.addCase()` lines each time
.addCase(decrement, (state, action) => {})
// You can match a range of action types
.addMatcher(
isRejectedAction,
// `action` will be inferred as a RejectedAction due to isRejectedAction being defined as a type guard
(state, action) => {}
)
// and provide a default case if no other handlers matched
.addDefaultCase((state, action) => {})
}
})
```
*/
extraReducers?:
| CaseReducers<NoInfer<State>, any>
| ((builder: ActionReducerMapBuilder<NoInfer<State>>) => void)
}
/**
* A CaseReducer with a `prepare` method.
*
* @public
*/
export type CaseReducerWithPrepare<State, Action extends PayloadAction> = {
reducer: CaseReducer<State, Action>
prepare: PrepareAction<Action['payload']>
}
/**
* The type describing a slice's `reducers` option.
*
* @public
*/
export type SliceCaseReducers<State> = {
[K: string]:
| CaseReducer<State, PayloadAction<any>>
| CaseReducerWithPrepare<State, PayloadAction<any, string, any, any>>
}
type SliceActionType<
SliceName extends string,
ActionName extends keyof any
> = ActionName extends string | number ? `${SliceName}/${ActionName}` : string
/**
* Derives the slice's `actions` property from the `reducers` options
*
* @public
*/
export type CaseReducerActions<
CaseReducers extends SliceCaseReducers<any>,
SliceName extends string
> = {
[Type in keyof CaseReducers]: CaseReducers[Type] extends { prepare: any }
? ActionCreatorForCaseReducerWithPrepare<
CaseReducers[Type],
SliceActionType<SliceName, Type>
>
: ActionCreatorForCaseReducer<
CaseReducers[Type],
SliceActionType<SliceName, Type>
>
}
/**
* Get a `PayloadActionCreator` type for a passed `CaseReducerWithPrepare`
*
* @internal
*/
type ActionCreatorForCaseReducerWithPrepare<
CR extends { prepare: any },
Type extends string
> = _ActionCreatorWithPreparedPayload<CR['prepare'], Type>
/**
* Get a `PayloadActionCreator` type for a passed `CaseReducer`
*
* @internal
*/
type ActionCreatorForCaseReducer<CR, Type extends string> = CR extends (
state: any,
action: infer Action
) => any
? Action extends { payload: infer P }
? PayloadActionCreator<P, Type>
: ActionCreatorWithoutPayload<Type>
: ActionCreatorWithoutPayload<Type>
/**
* Extracts the CaseReducers out of a `reducers` object, even if they are
* tested into a `CaseReducerWithPrepare`.
*
* @internal
*/
type SliceDefinedCaseReducers<CaseReducers extends SliceCaseReducers<any>> = {
[Type in keyof CaseReducers]: CaseReducers[Type] extends {
reducer: infer Reducer
}
? Reducer
: CaseReducers[Type]
}
/**
* Used on a SliceCaseReducers object.
* Ensures that if a CaseReducer is a `CaseReducerWithPrepare`, that
* the `reducer` and the `prepare` function use the same type of `payload`.
*
* Might do additional such checks in the future.
*
* This type is only ever useful if you want to write your own wrapper around
* `createSlice`. Please don't use it otherwise!
*
* @public
*/
export type ValidateSliceCaseReducers<
S,
ACR extends SliceCaseReducers<S>
> = ACR &
{
[T in keyof ACR]: ACR[T] extends {
reducer(s: S, action?: infer A): any
}
? {
prepare(...a: never[]): Omit<A, 'type'>
}
: {}
}
function getType(slice: string, actionKey: string): string {
return `${slice}/${actionKey}`
}
/**
* A function that accepts an initial state, an object full of reducer
* functions, and a "slice name", and automatically generates
* action creators and action types that correspond to the
* reducers and state.
*
* The `reducer` argument is passed to `createReducer()`.
*
* @public
*/
export function createSlice<
State,
CaseReducers extends SliceCaseReducers<State>,
Name extends string = string
>(
options: CreateSliceOptions<State, CaseReducers, Name>
): Slice<State, CaseReducers, Name> {
const { name } = options
if (!name) {
throw new Error('`name` is a required option for createSlice')
}
if (
typeof process !== 'undefined' &&
process.env.NODE_ENV === 'development'
) {
if (options.initialState === undefined) {
console.error(
'You must provide an `initialState` value that is not `undefined`. You may have misspelled `initialState`'
)
}
}
const initialState =
typeof options.initialState == 'function'
? options.initialState
: freezeDraftable(options.initialState)
const reducers = options.reducers || {}
const reducerNames = Object.keys(reducers)
const sliceCaseReducersByName: Record<string, CaseReducer> = {}
const sliceCaseReducersByType: Record<string, CaseReducer> = {}
const actionCreators: Record<string, Function> = {}
reducerNames.forEach((reducerName) => {
const maybeReducerWithPrepare = reducers[reducerName]
const type = getType(name, reducerName)
let caseReducer: CaseReducer<State, any>
let prepareCallback: PrepareAction<any> | undefined
if ('reducer' in maybeReducerWithPrepare) {
caseReducer = maybeReducerWithPrepare.reducer
prepareCallback = maybeReducerWithPrepare.prepare
} else {
caseReducer = maybeReducerWithPrepare
}
sliceCaseReducersByName[reducerName] = caseReducer
sliceCaseReducersByType[type] = caseReducer
actionCreators[reducerName] = prepareCallback
? createAction(type, prepareCallback)
: createAction(type)
})
function buildReducer() {
if (process.env.NODE_ENV !== 'production') {
if (typeof options.extraReducers === 'object') {
if (!hasWarnedAboutObjectNotation) {
hasWarnedAboutObjectNotation = true
console.warn(
"The object notation for `createSlice.extraReducers` is deprecated, and will be removed in RTK 2.0. Please use the 'builder callback' notation instead: https://redux-toolkit.js.org/api/createSlice"
)
}
}
}
const [
extraReducers = {},
actionMatchers = [],
defaultCaseReducer = undefined,
] =
typeof options.extraReducers === 'function'
? executeReducerBuilderCallback(options.extraReducers)
: [options.extraReducers]
const finalCaseReducers = { ...extraReducers, ...sliceCaseReducersByType }
return createReducer(initialState, (builder) => {
for (let key in finalCaseReducers) {
builder.addCase(key, finalCaseReducers[key] as CaseReducer<any>)
}
for (let m of actionMatchers) {
builder.addMatcher(m.matcher, m.reducer)
}
if (defaultCaseReducer) {
builder.addDefaultCase(defaultCaseReducer)
}
})
}
let _reducer: ReducerWithInitialState<State>
return {
name,
reducer(state, action) {
if (!_reducer) _reducer = buildReducer()
return _reducer(state, action)
},
actions: actionCreators as any,
caseReducers: sliceCaseReducersByName as any,
getInitialState() {
if (!_reducer) _reducer = buildReducer()
return _reducer.getInitialState()
},
}
}