Add flowcharts

Author: zoontek

README.md

@@ -66,7 +66,7 @@ Because this package targets React Native 0.60+, you will probably don't need to
 <details>
   <summary>👀 See manual linking instructions</summary>
 
-#### iOS
+### iOS
 
 Add this line to your `ios/Podfile` file, then run `pod install`.
 
@@ -116,8 +116,113 @@ public class MainApplication extends Application implements ReactApplication {
   // …
 }
 ```
+
 </details>
 
+## Permission lifecycles
+
+Permission are not handled in the same way on iOS and Android. This library provides an abstraction over the platforms behaviors. To understand it a little better, have a look to these two flowcharts:
+
+### iOS
+
+```
+   ┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
+   ┃ check(PERMISSIONS.IOS.CAMERA) ┃
+   ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
+                   │
+       Is the feature available
+           on this device ?
+                   │           ╔════╗
+                   ├───────────║ NO ║──────────────┐
+                   │           ╚════╝              │
+                ╔═════╗                            ▼
+                ║ YES ║                 ┌─────────────────────┐
+                ╚═════╝                 │ RESULTS.UNAVAILABLE │
+                   │                    └─────────────────────┘
+           Is the permission
+             requestable ?
+                   │           ╔════╗
+                   ├───────────║ NO ║──────────────┐
+                   │           ╚════╝              │
+                ╔═════╗                            ▼
+                ║ YES ║                  ┌───────────────────┐
+                ╚═════╝                  │ RESULTS.BLOCKED / │
+                   │                     │  RESULTS.GRANTED  │
+                   ▼                     └───────────────────┘
+          ┌────────────────┐
+          │ RESULTS.DENIED │
+          └────────────────┘
+                   │
+                   ▼
+  ┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
+  ┃ request(PERMISSIONS.IOS.CAMERA) ┃
+  ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
+                   │
+        Does the user accepted
+            the request ?
+                   │           ╔════╗
+                   ├───────────║ NO ║──────────────┐
+                   │           ╚════╝              │
+                ╔═════╗                            ▼
+                ║ YES ║                   ┌─────────────────┐
+                ╚═════╝                   │ RESULTS.BLOCKED │
+                   │                      └─────────────────┘
+                   ▼
+          ┌─────────────────┐
+          │ RESULTS.GRANTED │
+          └─────────────────┘
+```
+
+### Android
+
+```
+ ┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
+ ┃ check(PERMISSIONS.ANDROID.CAMERA) ┃
+ ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
+                   │
+       Is the feature available
+           on this device ?
+                   │           ╔════╗
+                   ├───────────║ NO ║──────────────┐
+                   │           ╚════╝              │
+                ╔═════╗                            ▼
+                ║ YES ║                 ┌─────────────────────┐
+                ╚═════╝                 │ RESULTS.UNAVAILABLE │
+                   │                    └─────────────────────┘
+           Is the permission
+             requestable ?
+                   │           ╔════╗
+                   ├───────────║ NO ║──────────────┐
+                   │           ╚════╝              │
+                ╔═════╗                            ▼
+                ║ YES ║                  ┌───────────────────┐
+                ╚═════╝                  │ RESULTS.BLOCKED / │
+                   │                     │  RESULTS.GRANTED  │
+                   ▼                     └───────────────────┘
+          ┌────────────────┐
+          │ RESULTS.DENIED │◀──────────────────────┐
+          └────────────────┘                       │
+                   │                               │
+                   ▼                               │
+┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓         ╔════╗
+┃ request(PERMISSIONS.ANDROID.CAMERA) ┃         ║ NO ║
+┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛         ╚════╝
+                   │                               │
+        Does the user accepted                     │
+            the request ?                          │
+                   │           ╔════╗    Does the user checked
+                   ├───────────║ NO ║─────"Never ask again" ?
+                   │           ╚════╝              │
+                ╔═════╗                         ╔═════╗
+                ║ YES ║                         ║ YES ║
+                ╚═════╝                         ╚═════╝
+                   │                               │
+                   ▼                               ▼
+          ┌─────────────────┐             ┌─────────────────┐
+          │ RESULTS.GRANTED │             │ RESULTS.BLOCKED │
+          └─────────────────┘             └─────────────────┘
+```
+
 ## API
 
 ### Permissions statuses