fix(overmind): resolve state of derived

Author: christianalfoni

packages/node_modules/overmind/src/derived.test.ts

@@ -7,10 +7,13 @@ type State = {
 
 describe('Derived', () => {
   test('should instantiate app with derived state', () => {
-    const derived: Derive<string> = (state) => state.foo.toUpperCase()
-    const state = {
+    type State = {
+      foo: string
+      upperFoo: Derive<string, State>
+    }
+    const state: State = {
       foo: 'bar',
-      upperFoo: derived,
+      upperFoo: (state) => state.foo.toUpperCase(),
     }
     const config = {
       state,
@@ -20,7 +23,7 @@ describe('Derived', () => {
       state: typeof state
     }>
 
-    type Derive<Value> = TDerive<IApp, Value>
+    type Derive<Value, Parent extends object> = TDerive<IApp, Value, Parent>
 
     const app = new Overmind(config)
 
@@ -30,14 +33,17 @@ describe('Derived', () => {
   test('should track derived state', () => {
     let renderCount = 0
     const changeFoo: Action = ({ state }) => (state.foo = 'bar2')
-
-    const derived: Derive<string> = (state) => state.foo.toUpperCase()
+    type State = {
+      foo: string
+      upperFoo: Derive<string, State>
+    }
+    const state: State = {
+      foo: 'bar',
+      upperFoo: (state) => state.foo.toUpperCase(),
+    }
 
     const config = {
-      state: {
-        foo: 'bar',
-        upperFoo: derived,
-      },
+      state,
       actions: {
         changeFoo,
       },
@@ -50,7 +56,7 @@ describe('Derived', () => {
       actions: typeof config.actions
     }>
     type Action<Input = void> = TAction<IApp, Input>
-    type Derive<Value> = TDerive<IApp, Value>
+    type Derive<Value, Parent extends object> = TDerive<IApp, Value, Parent>
 
     const app = new Overmind(config)
     function render() {
@@ -67,18 +73,21 @@ describe('Derived', () => {
   })
   test('should not require flush to flag as dirty', () => {
     expect.assertions(1)
+    type State = {
+      foo: string
+      upperFoo: Derive<string, State>
+    }
+    const state: State = {
+      foo: 'bar',
+      upperFoo: (state) => state.foo.toUpperCase(),
+    }
     const changeFoo: Action = ({ state }) => {
       state.foo = 'bar2'
       expect(state.upperFoo).toBe('BAR2')
     }
 
-    const derived: Derive<string> = (state) => state.foo.toUpperCase()
-
     const config = {
-      state: {
-        foo: 'bar',
-        upperFoo: derived,
-      },
+      state,
       actions: {
         changeFoo,
       },
@@ -91,7 +100,7 @@ describe('Derived', () => {
       actions: typeof config.actions
     }>
     type Action<Input = void> = TAction<IApp, Input>
-    type Derive<Value> = TDerive<IApp, Value>
+    type Derive<Value, Parent extends object> = TDerive<IApp, Value, Parent>
 
     const app = new Overmind(config)
 
@@ -124,7 +133,7 @@ describe('Derived', () => {
       actions: typeof config.actions
     }>
     type Action<Input = void> = TAction<IApp, Input>
-    type Derive<Value, Parent = any> = TDerive<IApp, Value, Parent>
+    type Derive<Value, Parent extends object> = TDerive<IApp, Value, Parent>
 
     const app = new Overmind(config)
 

packages/node_modules/overmind/src/types.ts

@@ -50,8 +50,8 @@ export type TOperator<Input, Output, OperatorContext extends TContext<any>> = (
   final?: (err, Error, val?: TValueContext<OperatorContext, Output>) => void
 ) => void
 
-export type TDerive<App extends BaseApp, Value, Parent = any> = (
-  parent: Parent,
+export type TDerive<App extends BaseApp, Value, Parent extends object = {}> = (
+  parent: ResolveState<Parent>,
   state: App['state']
 ) => Value