add/update docblocks

src/createReducer.ts

@@ -56,7 +56,21 @@ export function createReducer<
   S,
   CR extends CaseReducers<S, any> = CaseReducers<S, any>
 >(initialState: S, actionsMap: CR): Reducer<S>
-
+/**
+ * A utility function that allows defining a reducer as a mapping from action
+ * type to *case reducer* functions that handle these action types. The
+ * reducer's initial state is passed as the first argument.
+ *
+ * The body of every case reducer is implicitly wrapped with a call to
+ * `produce()` from the [immer](https://github.com/mweststrate/immer) library.
+ * This means that rather than returning a new state object, you can also
+ * mutate the passed-in state object directly; these mutations will then be
+ * automatically and efficiently translated into copies, giving you both
+ * convenience and immutability.
+ * @param initialState The initial state to be returned by the reducer.
+ * @param builderCallback A callback that receives a *builder* object to define
+ *   case reducers via calls to `builder.addCase(actionCreatorOrType, reducer)`.
+ */
 export function createReducer<S>(
   initialState: S,
   builderCallback: (builder: ActionReducerMapBuilder<S>) => void

src/createSlice.ts

@@ -76,6 +76,8 @@ export interface CreateSliceOptions<
    * 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.
+   * Alternatively, a callback that receives a *builder* object to define
+   * case reducers via calls to `builder.addCase(actionCreatorOrType, reducer)`.
    */
   extraReducers?:
     | CaseReducers<NoInfer<State>, any>

src/mapBuilders.ts

@@ -6,11 +6,24 @@ export interface TypedActionCreator<Type extends string> {
   type: Type
 }
 
+/**
+ * A builder for an action <-> reducer map.
+ */
 export interface ActionReducerMapBuilder<State> {
+  /**
+   * Add a case reducer for actions created by this action creator.
+   * @param actionCreator
+   * @param reducer
+   */
   addCase<ActionCreator extends TypedActionCreator<string>>(
     actionCreator: ActionCreator,
     reducer: CaseReducer<State, ReturnType<ActionCreator>>
   ): ActionReducerMapBuilder<State>
+  /**
+   * Add a case reducer for actions with the specified type.
+   * @param type
+   * @param reducer
+   */
   addCase<Type extends string, A extends Action<Type>>(
     type: Type,
     reducer: CaseReducer<State, A>