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reduced typings some more

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Ken
2019-01-31 14:45:33 -08:00
parent 2ecb667b3a
commit 886215cefa
4 changed files with 26 additions and 18 deletions
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9
playground/src/actions/index.ts
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@@ -1,4 +1,4 @@
import { action } from '../redux-utils/action'; import { action, GenericActionTypes, GenericAction, GenericActionLookup, GenericActionMapping } from '../redux-utils/action';
export const actions = { export const actions = {
add: (label: string) => action('add', { label }), add: (label: string) => action('add', { label }),
@@ -9,6 +9,7 @@ export const actions = {
filter: (filterTypes: string) => action('filter', { filter: filterTypes }) filter: (filterTypes: string) => action('filter', { filter: filterTypes })
}; };
export type ActionTypes = ReturnType<typeof actions[keyof typeof actions]>['type']; export type ActionMap = GenericActionMapping<typeof actions>;
export type TodoAction = ReturnType<typeof actions[ActionTypes]>; export type ActionTypes = GenericActionTypes<ActionMap>;
export type TodoActionLookup = { [a in ActionTypes]: ReturnType<typeof actions[a]> }; export type TodoAction = GenericAction<ActionMap>;
export type TodoActionLookup = GenericActionLookup<ActionMap>;

11
playground/src/reducers/createReducer.ts
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@@ -1,9 +1,10 @@
import { ActionTypes, TodoActionLookup } from '../actions'; import { ActionTypes, TodoActionLookup, actions } from '../actions';
import { createGenericReducer, HandlerMap, ImmerReducer } from '../redux-utils/reducer'; import { createGenericReducer, HandlerMap, ImmerReducer } from '../redux-utils/reducer';
import { Reducer } from 'redux';
export function createReducer<T, AT extends ActionTypes | never = never>( export function createReducer<T, AM extends ActionTypes | never = never>(
initialState: T, initialState: T,
handlerOrMap: HandlerMap<T, ActionTypes, TodoActionLookup> | ImmerReducer<T, TodoActionLookup[AT]> handlerOrMap: HandlerMap<T, typeof actions> | ImmerReducer<T, TodoActionLookup[AM]>
) { ): Reducer<T> {
return createGenericReducer(initialState, handlerOrMap); return createGenericReducer<T, typeof actions, AM>(initialState, handlerOrMap);
} }

5
playground/src/redux-utils/action.ts
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@@ -7,3 +7,8 @@ export function action<T extends string, P>(type: T, payload: P): ActionWithPayl
export function action<T extends string, P>(type: T, payload?: P) { export function action<T extends string, P>(type: T, payload?: P) {
return { type, ...payload }; return { type, ...payload };
} }
export type GenericActionMapping<A> = { [somekey in keyof A]: (...args: any) => Action<any> | ActionWithPayload<any, any> };
export type GenericActionTypes<A extends GenericActionMapping<A>> = ReturnType<A[keyof A]>['type'];
export type GenericAction<A extends GenericActionMapping<A>> = ReturnType<A[GenericActionTypes<A>]>;
export type GenericActionLookup<A extends GenericActionMapping<A>> = { [a in GenericActionTypes<A>]: ReturnType<A[a]> };

19
playground/src/redux-utils/reducer.ts
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@@ -1,13 +1,14 @@
import { Reducer } from 'redux'; import { Reducer } from 'redux';
import { Draft, produce } from 'immer'; import { Draft, produce } from 'immer';
import { GenericActionLookup, GenericActionMapping } from './action';
export type ImmerReducer<T, A> = (state: Draft<T>, action?: A) => T; export type ImmerReducer<T, A> = (state: Draft<T>, action?: A) => T;
export type HandlerMap<T, AT extends string, Lookup extends { [t in AT]: any }> = { export type HandlerMap<T, A extends GenericActionMapping<A>> = {
[actionType in AT]?: ImmerReducer<T, Lookup[actionType]> [actionType in keyof A]?: ImmerReducer<T, GenericActionLookup<A>[actionType]>
}; };
function isHandlerFunction<T, A, AT extends string, Lookup extends { [t in AT]: any }>( function isHandlerFunction<T, A extends GenericActionMapping<A>>(
handlerOrMap: HandlerMap<T, AT, Lookup> | ImmerReducer<T, A> handlerOrMap: HandlerMap<T, A> | ImmerReducer<T, A>
): handlerOrMap is ImmerReducer<T, A> { ): handlerOrMap is ImmerReducer<T, A> {
if (typeof handlerOrMap === 'function') { if (typeof handlerOrMap === 'function') {
return true; return true;
@@ -16,15 +17,15 @@ function isHandlerFunction<T, A, AT extends string, Lookup extends { [t in AT]:
return false; return false;
} }
export function createGenericReducer<T, AT extends string, Lookup extends { [t in AT]: any }>( export function createGenericReducer<T, A extends GenericActionMapping<A>, AM = keyof GenericActionMapping<A>>(
initialState: T, initialState: T,
handlerOrMap: HandlerMap<T, AT, Lookup> | ImmerReducer<T, Lookup[AT]> handlerOrMap: HandlerMap<T, A> | ImmerReducer<T, GenericActionLookup<A>[AM]>
): Reducer<T> { ): Reducer<T> {
return function reducer(state = initialState, action: Lookup[AT]): T { return function reducer(state = initialState, action: GenericActionLookup<A>[AM]): T {
if (isHandlerFunction(handlerOrMap)) { if (isHandlerFunction(handlerOrMap)) {
return produce(state, draft => handlerOrMap(draft, action as Lookup[AT])); return produce(state, draft => handlerOrMap(draft, action as GenericActionLookup<A>[AM]));
} else if (handlerOrMap.hasOwnProperty(action.type)) { } else if (handlerOrMap.hasOwnProperty(action.type)) {
const handler = (handlerOrMap as any)[action.type] as ImmerReducer<T, Lookup[AT]>; const handler = (handlerOrMap as any)[action.type] as ImmerReducer<T, GenericActionLookup<A>[AM]>;
return produce(state, draft => handler(draft, action)); return produce(state, draft => handler(draft, action));
} else { } else {
return state; return state;