wip

Author: tony-go

src/connect/wrapMapToProps.ts

@@ -3,18 +3,23 @@ import { Dispatch } from 'redux'
 import { FixTypeLater } from '../types'
 import verifyPlainObject from '../utils/verifyPlainObject'
 
-export type MapToProps = {
-  (stateOrDispatch: FixTypeLater, ownProps?: unknown): FixTypeLater
+type AnyState = { [key: string]: any }
+type StateOrDispatch<S = AnyState> = S | Dispatch
+
+type AnyProps = { [key: string]: any }
+
+export type MapToProps<P = AnyProps> = {
+  (stateOrDispatch: StateOrDispatch, ownProps?: P): FixTypeLater
   dependsOnOwnProps: boolean
 }
 
 export function wrapMapToPropsConstant(
   // * Note:
-  //  It seems that the dispatch identifier here
-  //  could be dispatch in some cases (ex: whenMapDispatchToPropsIsMissing)
-  // and state in some others (ex: whenMapStateToPropsIsMissing)
+  //  It seems that the dispatch argument
+  //  could be a dispatch function in some cases (ex: whenMapDispatchToPropsIsMissing)
+  //  and a state object in some others (ex: whenMapStateToPropsIsMissing)
   //
-  getConstant: (dispatch: Dispatch) => FixTypeLater
+  getConstant: (dispatch: Dispatch) => { dispatch: Dispatch }
 ) {
   return function initConstantSelector(dispatch: Dispatch) {
     const constant = getConstant(dispatch)
@@ -52,26 +57,29 @@ export function getDependsOnOwnProps(mapToProps: MapToProps) {
 //  * On first call, verifies the first result is a plain object, in order to warn
 //    the developer that their mapToProps function is not returning a valid result.
 //
-export function wrapMapToPropsFunc(mapToProps: MapToProps, methodName: string) {
+export function wrapMapToPropsFunc<P = AnyProps>(
+  mapToProps: MapToProps,
+  methodName: string
+) {
   return function initProxySelector(
     dispatch: Dispatch,
     { displayName }: { displayName: string }
   ) {
     const proxy = function mapToPropsProxy(
       stateOrDispatch: FixTypeLater,
-      ownProps: unknown
+      ownProps?: P
     ): FixTypeLater {
       return proxy.dependsOnOwnProps
         ? proxy.mapToProps(stateOrDispatch, ownProps)
-        : proxy.mapToProps(stateOrDispatch, null)
+        : proxy.mapToProps(stateOrDispatch, undefined)
     }
 
     // allow detectFactoryAndVerify to get ownProps
     proxy.dependsOnOwnProps = true
 
     proxy.mapToProps = function detectFactoryAndVerify(
       stateOrDispatch: FixTypeLater,
-      ownProps: unknown
+      ownProps?: P
     ) {
       proxy.mapToProps = mapToProps
       proxy.dependsOnOwnProps = getDependsOnOwnProps(mapToProps)

test/components/connect.spec.js

@@ -2626,7 +2626,7 @@ describe('React', () => {
         expect(memoizedReturnCount).toBe(2)
       })
 
-      it('should allow a mapStateToProps factory consuming just state to return a function that gets ownProps', () => {
+      it.only('should allow a mapStateToProps factory consuming just state to return a function that gets ownProps', () => {
         const store = createStore(() => ({ value: 1 }))
 
         let initialState
@@ -2660,7 +2660,7 @@ describe('React', () => {
           store.dispatch({ type: 'test' })
         })
 
-        expect(initialOwnProps).toBe(null)
+        expect(initialOwnProps).toBe(undefined)
         expect(initialState).not.toBe(undefined)
         expect(secondaryOwnProps).not.toBe(undefined)
         expect(secondaryOwnProps.name).toBe('a')