ImagePickerIOS: Add documentation (#546)

Author: sgny

reason-react-native/src/apis/ImagePickerIOS.md

@@ -1,47 +1,117 @@
 ---
 id: apis/ImagePickerIOS
 title: ImagePickerIOS
-wip: true
+officialDoc: https://facebook.github.io/react-native/docs/imagepickerios
 ---
 
+## Note
+
+This API will be removed from React Native as part of the
+[_Lean Core_](https://github.com/facebook/react-native/issues/23313) effort.
+While it has already been moved to a community
+[repo](https://github.com/react-native-community/react-native-image-picker-ios),
+more current packages such as
+[`react-native-image-picker`](https://github.com/react-native-community/react-native-image-picker)
+and [`expo-image-picker`](https://docs.expo.io/versions/latest/sdk/imagepicker/)
+are recommended instead.
+
+---
+
+Before you may use this API, you need to link the `RCTCameraRoll` library to
+your app and provide a description for your use of the Photo Library.
+
+- you need to add `RCTCameraRoll.xcodeproj` (located in the
+  `node_modules/react-native/Libraries/CameraRoll` subdirectory of your app) to
+  your project's Libraries tree in XCode, then
+- you need to specify `libRCTCameraRoll.a` under _Link Binary with Libraries_ in
+  your app's _Build Phases_ tab.
+- you also need to set the _Privacy - Photo Library Usage Description_ (or
+  _NSPhotoLibraryUsageDescription_) key under _Custom iOS Target Properties_ in
+  your apps' _Info_ tab.
+
+## Types
+
+### `imageUri`
+
+An alias for the `string` type
+
 ```reason
-type imageUri = string;
+type imageUri = string
+```
+
+### `cameraDialogConfig`
+
+An abstract type which can be created using the constructor of the same name.
+You may call the constructor as `cameraDialogConfig()` to use the default
+values.
 
-[@bs.module "react-native"] [@bs.scope "ImagePickerIOS"]
-external canUseCamera: (bool => unit) => unit = "";
+```reason
+cameraDialogConfig: (~videoMode: bool=?, unit) => cameraDialogConfig
+```
 
-[@bs.module "react-native"] [@bs.scope "ImagePickerIOS"]
-external canRecordVideos: (bool => unit) => unit = "";
+### `selectDialogConfig`
+
+An abstract type which can be created using the constructor of the same name.
+You may call the constructor as `selectDialogConfig()` to use the default
+values.
+
+```reason
+selectDialogConfig:
+  (~showImages: bool=?, ~showVideos: bool=?, unit) => selectDialogConfig
+```
 
-type cameraDialogConfig;
-[@bs.obj]
-external cameraDialogConfig: (~videoMode: bool=?, unit) => cameraDialogConfig =
-  "";
+## Methods
 
-type selectDialogConfig;
-[@bs.obj]
-external selectDialogConfig:
-  (~showImages: bool=?, ~showVideos: bool=?, unit) => selectDialogConfig =
-  "";
+### `canUseCamera`
 
-[@bs.module "react-native"] [@bs.scope "ImagePickerIOS"]
-external openCameraDialog:
+Method to check whether the app has permissions to use the camera, takes a
+callback of type `bool => unit`.
+
+```reason
+canUseCamera: (bool => unit) => unit
+```
+
+### `canRecordVideos`
+
+Method to check whether the app has permissions to record videos, takes a
+callback of type `bool => unit`.
+
+```reason
+canRecordVideos: (bool => unit) => unit
+```
+
+### `openCameraDialog`
+
+Method to request the Camera dialog given a config (of type
+[`cameraDialogConfig`](#cameraDialogConfig)) to specify whether the camera is
+launched in video mode. When an image or video is captured, `onSuccess` callback
+is passed the returned `imageUri`, `height` and `width`; `onError` callback is
+applied otherwise. As`'error` is an abstract type
+
+```reason
+openCameraDialog:
   (
     ~config: cameraDialogConfig,
-    ~onSuccess: imageUri => unit,
+    ~onSuccess: (imageUri, ~height: float, ~width: float, unit) => unit,
     ~onError: 'error => unit
   ) =>
-  unit =
-  "";
+  unit
+```
 
-[@bs.module "react-native"] [@bs.scope "ImagePickerIOS"]
-external openSelectDialog:
+### `openSelectDialog`
+
+Method to request the Image Gallery given a config (of type
+[`openSelectDialog`](#openSelectDialog)) to specify whether images and/or videos
+should be listed. When an image or video is selected, `onSuccess` callback is
+passed the returned `imageUri`, `height` and `width`; `onError` callback is
+executed otherwise. As`'error` is an abstract type
+
+```reason
+openSelectDialog:
   (
     ~config: selectDialogConfig,
-    ~onSuccess: imageUri => unit,
+    ~onSuccess: (imageUri, ~height: float, ~width: float, unit) => unit,
     ~onError: 'error => unit
   ) =>
-  unit =
-  "";
-
+  unit
 ```