Add defaultValue and initialValue (#98)

Author: PerfectPixel

README.md

@@ -97,6 +97,8 @@ const MyForm = () => (
     - [`component?: React.ComponentType<FieldArrayRenderProps>`](#component-reactcomponenttypefieldarrayrenderprops)
     - [`name: string`](#name-string)
     - [`render?: (props: FieldArrayRenderProps) => React.Node`](#render-props-fieldarrayrenderprops--reactnode)
+    - [`defaultValue?: any`](#defaultvalue-any)
+    - [`initialValue?: any`](#initialvalue-any)
     - [`isEqual?: (allPreviousValues: Array<any>, allNewValues: Array<any>) => boolean`](#isequal-allpreviousvalues-arrayany-allnewvalues-arrayany--boolean)
     - [`subscription?: FieldSubscription`](#subscription-fieldsubscription)
     - [`validate?: (value: ?any[], allValues: Object) => ?any`](#validate-value-any-allvalues-object--any)
@@ -200,6 +202,16 @@ A render function that is given
 [`FieldArrayRenderProps`](#fieldarrayrenderprops), as well as any non-API props
 passed into the `<FieldArray/>` component.
 
+#### `defaultValue?: any`
+
+⚠️ You probably want `initialValue`! ⚠️
+
+_**Before using this prop, read and understand the 🏁 Final Form documentation on [`initialValue`](https://github.com/final-form/final-form#initialvalue-any) and [`defaultValue`](https://github.com/final-form/final-form#defaultvalue-any)!**_
+
+#### `initialValue?: any`
+
+[See the 🏁 Final Form docs on `initialValue`](https://github.com/final-form/final-form#initialvalue-any)
+
 #### `isEqual?: (allPreviousValues: Array<any>, allNewValues: Array<any>) => boolean`
 
 A function that can be used to compare two arrays of values (before and after every change) and calculate pristine/dirty checks. Defaults to a function that will `===` check each element of the array.

src/FieldArray.js

@@ -17,12 +17,16 @@ const versions = {
 const FieldArray = ({
   name,
   subscription,
+  defaultValue,
+  initialValue,
   isEqual,
   validate,
   ...rest
 }: FieldArrayProps) => {
   const { fields, meta } = useFieldArray(name, {
     subscription,
+    defaultValue,
+    initialValue,
     isEqual,
     validate
   })

src/types.js.flow

@@ -48,6 +48,8 @@ export type RenderableProps<T> = $Shape<{
 
 export type UseFieldArrayConfig = {
   subscription?: FieldSubscription,
+  defaultValue?: any,
+  initialValue?: any,
   isEqual?: (any[], any[]) => boolean,
   validate?: (value: ?(any[]), allValues: Object, meta: ?FieldState) => ?any
 }

src/useFieldArray.js

@@ -16,6 +16,8 @@ const useFieldArray = (
   name: string,
   {
     subscription = all,
+    defaultValue,
+    initialValue,
     isEqual = defaultIsEqual,
     validate: validateProp
   }: UseFieldArrayConfig = {}
@@ -58,6 +60,8 @@ const useFieldArray = (
     ...fieldState
   } = useField(name, {
     subscription: { ...subscription, length: true },
+    defaultValue,
+    initialValue,
     isEqual,
     validate,
     format: v => v