From 03956406fb85499212fcc6c8b3f3d3cb7c48c7a8 Mon Sep 17 00:00:00 2001
From: Johan Lindskogen <johan.lindskogen@gmail.com>
Date: Tue, 6 Jul 2021 07:44:50 +0000
Subject: [PATCH] Add types for mergeProps file

---
 src/connect/mergeProps.js | 44 --------------------------------
 src/connect/mergeProps.ts | 53 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 44 deletions(-)
 delete mode 100644 src/connect/mergeProps.js
 create mode 100644 src/connect/mergeProps.ts

diff --git a/src/connect/mergeProps.js b/src/connect/mergeProps.js
deleted file mode 100644
index ca21ea0a6..000000000
--- a/src/connect/mergeProps.js
+++ /dev/null
@@ -1,44 +0,0 @@
-import verifyPlainObject from '../utils/verifyPlainObject'
-
-export function defaultMergeProps(stateProps, dispatchProps, ownProps) {
-  return { ...ownProps, ...stateProps, ...dispatchProps }
-}
-
-export function wrapMergePropsFunc(mergeProps) {
-  return function initMergePropsProxy(
-    dispatch,
-    { displayName, pure, areMergedPropsEqual }
-  ) {
-    let hasRunOnce = false
-    let mergedProps
-
-    return function mergePropsProxy(stateProps, dispatchProps, ownProps) {
-      const nextMergedProps = mergeProps(stateProps, dispatchProps, ownProps)
-
-      if (hasRunOnce) {
-        if (!pure || !areMergedPropsEqual(nextMergedProps, mergedProps))
-          mergedProps = nextMergedProps
-      } else {
-        hasRunOnce = true
-        mergedProps = nextMergedProps
-
-        if (process.env.NODE_ENV !== 'production')
-          verifyPlainObject(mergedProps, displayName, 'mergeProps')
-      }
-
-      return mergedProps
-    }
-  }
-}
-
-export function whenMergePropsIsFunction(mergeProps) {
-  return typeof mergeProps === 'function'
-    ? wrapMergePropsFunc(mergeProps)
-    : undefined
-}
-
-export function whenMergePropsIsOmitted(mergeProps) {
-  return !mergeProps ? () => defaultMergeProps : undefined
-}
-
-export default [whenMergePropsIsFunction, whenMergePropsIsOmitted]
diff --git a/src/connect/mergeProps.ts b/src/connect/mergeProps.ts
new file mode 100644
index 000000000..a6aeac91d
--- /dev/null
+++ b/src/connect/mergeProps.ts
@@ -0,0 +1,53 @@
+import { Dispatch } from 'redux'
+import verifyPlainObject from '../utils/verifyPlainObject'
+
+type MergeProps<TStateProps, TDispatchProps, TOwnProps, TMergedProps> = (stateProps: TStateProps, dispatchProps: TDispatchProps, ownProps: TOwnProps) => TMergedProps
+
+export function defaultMergeProps<TStateProps, TDispatchProps, TOwnProps>(stateProps: TStateProps, dispatchProps: TDispatchProps, ownProps: TOwnProps) {
+  return { ...ownProps, ...stateProps, ...dispatchProps }
+}
+
+interface InitMergeOptions { 
+  displayName: string;
+  pure?: boolean;
+  areMergedPropsEqual: (a: any, b: any) => boolean;
+}
+
+export function wrapMergePropsFunc<TStateProps, TDispatchProps, TOwnProps, TMergedProps>(mergeProps: MergeProps<TStateProps, TDispatchProps, TOwnProps, TMergedProps>): (dispatch: Dispatch, options: InitMergeOptions) => MergeProps<TStateProps, TDispatchProps, TOwnProps, TMergedProps> {
+  return function initMergePropsProxy(
+    dispatch,
+    { displayName, pure, areMergedPropsEqual }
+  ) {
+    let hasRunOnce = false
+    let mergedProps: TMergedProps
+
+    return function mergePropsProxy(stateProps: TStateProps, dispatchProps: TDispatchProps, ownProps: TOwnProps) {
+      const nextMergedProps = mergeProps(stateProps, dispatchProps, ownProps)
+
+      if (hasRunOnce) {
+        if (!pure || !areMergedPropsEqual(nextMergedProps, mergedProps))
+          mergedProps = nextMergedProps
+      } else {
+        hasRunOnce = true
+        mergedProps = nextMergedProps
+
+        if (process.env.NODE_ENV !== 'production')
+          verifyPlainObject(mergedProps, displayName, 'mergeProps')
+      }
+
+      return mergedProps
+    }
+  }
+}
+
+export function whenMergePropsIsFunction<TStateProps, TDispatchProps, TOwnProps, TMergedProps>(mergeProps: MergeProps<TStateProps, TDispatchProps, TOwnProps, TMergedProps>) {
+  return typeof mergeProps === 'function'
+    ? wrapMergePropsFunc(mergeProps)
+    : undefined
+}
+
+export function whenMergePropsIsOmitted<TStateProps, TDispatchProps, TOwnProps, TMergedProps>(mergeProps?: MergeProps<TStateProps, TDispatchProps, TOwnProps, TMergedProps>) {
+  return !mergeProps ? () => defaultMergeProps : undefined
+}
+
+export default [whenMergePropsIsFunction, whenMergePropsIsOmitted] as const