Add resetState, reset to powerplug

docs/components/Value.md

@@ -57,3 +57,7 @@ Your value state
 **set**  
 `(value: T | (value: T) => T) => void`  
 Set or over the value state
+
+**reset**  
+`() => void`  
+Reset value to initial

src/components/Value.js

@@ -9,10 +9,11 @@ const Value = ({ initial, onChange, ...props }) => (
     initial={{ value: initial }}
     onChange={onChangeProp(onChange, 'value')}
   >
-    {({ state, setState }) =>
+    {({ state, setState, resetState }) =>
       renderProps(props, {
         value: state.value,
         set: value => setState(s => ({ value: set(value, s.value) })),
+        reset: () => resetState(),
       })
     }
   </State>

src/index.js.flow

@@ -269,6 +269,7 @@ type ValueChange<T> = (value: T) => void
 type ValueRender<T> = ({|
   value: T,
   set: Updater<T>,
+  reset: () => void,
 |}) => React.Node
 
 type ValueProps<T> =

tests/components/Value.test.js

@@ -5,7 +5,9 @@ import { lastCallArg } from './utils'
 
 test('<Value />', () => {
   const renderFn = jest.fn().mockReturnValue(null)
-  TestRenderer.create(<Value initial={{ a: 1 }} render={renderFn} />)
+  const testRenderer = TestRenderer.create(
+    <Value initial={{ a: 1 }} render={renderFn} />
+  )
 
   expect(renderFn).toBeCalledTimes(1)
 
@@ -21,6 +23,13 @@ test('<Value />', () => {
 
   lastCallArg(renderFn).set(0)
   expect(renderFn).lastCalledWith(expect.objectContaining({ value: 0 }))
+
+  // test reset
+  testRenderer.update(<Value initial={3} render={renderFn} />)
+  expect(renderFn).lastCalledWith(expect.objectContaining({ value: 0 }))
+
+  lastCallArg(renderFn).reset()
+  expect(renderFn).lastCalledWith(expect.objectContaining({ value: 3 }))
 })
 
 test('<Value onChange />', () => {

tests/test_flow.js

@@ -540,7 +540,7 @@ const noop = () => null
 
 /* Value with inferred generic */
 {
-  const render = ({ value, set }) => {
+  const render = ({ value, set, reset }) => {
     ;(value: number | string | boolean)
     // $FlowFixMe
     ;(value: number)
@@ -549,6 +549,10 @@ const noop = () => null
     // $FlowFixMe
     ;(value: boolean)
     set(true)
+
+    reset()
+    // $FlowFixMe
+    reset(1)
   }
   const onChange = value => {
     ;(value: number | string)