doc to readme for usage

README.md

@@ -36,10 +36,148 @@
 
 
 ## Usage
-```javascript
+---
-import RNCCameraroll from '@react-native-community/cameraroll';
+id: cameraroll
+title: CameraRoll
+---
 
-// TODO: What to do with the module?
+`CameraRoll` provides access to the local camera roll or photo library.
-RNCCameraroll;
+
+On iOS, the `CameraRoll` API requires the `RCTCameraRoll` library to be linked. You can refer to [Linking Libraries (iOS)](linking-libraries-ios.md) to learn more.
+
+### Permissions
+
+The user's permission is required in order to access the Camera Roll on devices running iOS 10 or later. Add the `NSPhotoLibraryUsageDescription` key in your `Info.plist` with a string that describes how your app will use this data. This key will appear as `Privacy - Photo Library Usage Description` in Xcode.
+
+If you are targeting devices running iOS 11 or later, you will also need to add the `NSPhotoLibraryAddUsageDescription` key in your `Info.plist`. Use this key to define a string that describes how your app will use this data. By adding this key to your `Info.plist`, you will be able to request write-only access permission from the user. If you try to save to the camera roll without this permission, your app will exit.
+
+### Methods
+
+* [`saveToCameraRoll`](cameraroll.md#savetocameraroll)
+* [`getPhotos`](cameraroll.md#getphotos)
+
+---
+
+# Reference
+
+## Methods
+
+### `saveToCameraRoll()`
+
+```javascript
+CameraRoll.saveToCameraRoll(tag, [type]);
 ```
-  
+
+Saves the photo or video to the camera roll or photo library.
+
+On Android, the tag must be a local image or video URI, such as `"file:///sdcard/img.png"`.
+
+On iOS, the tag can be any image URI (including local, remote asset-library and base64 data URIs) or a local video file URI (remote or data URIs are not supported for saving video at this time).
+
+If the tag has a file extension of .mov or .mp4, it will be inferred as a video. Otherwise it will be treated as a photo. To override the automatic choice, you can pass an optional `type` parameter that must be one of 'photo' or 'video'.
+
+Returns a Promise which will resolve with the new URI.
+
+**Parameters:**
+
+| Name | Type                   | Required | Description                                                |
+| ---- | ---------------------- | -------- | ---------------------------------------------------------- |
+| tag  | string                 | Yes      | See above.                                                 |
+| type | enum('photo', 'video') | No       | Overrides automatic detection based on the file extension. |
+
+---
+
+### `getPhotos()`
+
+```javascript
+CameraRoll.getPhotos(params);
+```
+
+Returns a Promise with photo identifier objects from the local camera roll of the device matching shape defined by `getPhotosReturnChecker`.
+
+**Parameters:**
+
+| Name   | Type   | Required | Description                                      |
+| ------ | ------ | -------- | ------------------------------------------------ |
+| params | object | Yes      | Expects a params with the shape described below. |
+
+* `first` : {number} : The number of photos wanted in reverse order of the photo application (i.e. most recent first for SavedPhotos).
+* `after` : {string} : A cursor that matches `page_info { end_cursor }` returned from a previous call to `getPhotos`.
+* `groupTypes` : {string} : Specifies which group types to filter the results to. Valid values are:
+  * `Album`
+  * `All`
+  * `Event`
+  * `Faces`
+  * `Library`
+  * `PhotoStream`
+  * `SavedPhotos` // default
+* `groupName` : {string} : Specifies filter on group names, like 'Recent Photos' or custom album titles.
+* `assetType` : {string} : Specifies filter on asset type. Valid values are:
+  * `All`
+  * `Videos`
+  * `Photos` // default
+* `mimeTypes` : {Array} : Filter by mimetype (e.g. image/jpeg).
+
+Returns a Promise which when resolved will be of the following shape:
+
+* `edges` : {Array<node>} An array of node objects
+  * `node`: {object} An object with the following shape:
+    * `type`: {string}
+    * `group_name`: {string}
+    * `image`: {object} : An object with the following shape:
+      * `uri`: {string}
+      * `height`: {number}
+      * `width`: {number}
+      * `isStored`: {boolean}
+      * `playableDuration`: {number}
+    * `timestamp`: {number}
+    * `location`: {object} : An object with the following shape:
+      * `latitude`: {number}
+      * `longitude`: {number}
+      * `altitude`: {number}
+      * `heading`: {number}
+      * `speed`: {number}
+* `page_info` : {object} : An object with the following shape:
+  * `has_next_page`: {boolean}
+  * `start_cursor`: {string}
+  * `end_cursor`: {string}
+
+#### Example
+
+Loading images:
+
+```javascript
+_handleButtonPress = () => {
+   CameraRoll.getPhotos({
+       first: 20,
+       assetType: 'Photos',
+     })
+     .then(r => {
+       this.setState({ photos: r.edges });
+     })
+     .catch((err) => {
+        //Error Loading Images
+     });
+   };
+render() {
+ return (
+   <View>
+     <Button title="Load Images" onPress={this._handleButtonPress} />
+     <ScrollView>
+       {this.state.photos.map((p, i) => {
+       return (
+         <Image
+           key={i}
+           style={{
+             width: 300,
+             height: 100,
+           }}
+           source={{ uri: p.node.image.uri }}
+         />
+       );
+     })}
+     </ScrollView>
+   </View>
+ );
+}
+```