🌊 Add Expo managed workflow support for SDK 39+

This is done by using the ExpoRandom native module if it exists.

Author: brentvatne

getRandomBase64.expo.js

@@ -0,0 +1,8 @@
+import { NativeModules } from 'react-native';
+
+// In the Expo managed workflow the getRandomBase64 method is provided by ExpoRandom.getRandomBase64String
+if (!NativeModules.ExpoRandom) {
+  throw new Error('Expo managed workflow support for react-native-get-random-values is only available in SDK 39 and higher.');
+}
+
+export default NativeModules.ExpoRandom.getRandomBase64String;

getRandomBase64.js

@@ -0,0 +1,3 @@
+import { NativeModules } from 'react-native';
+
+export default NativeModules.RNGetRandomValues.getRandomBase64;

index.js

@@ -1,5 +1,5 @@
-const RNGetRandomValues = require('react-native').NativeModules.RNGetRandomValues
-const base64Decode = require('fast-base64-decode')
+import getRandomBase64 from './getRandomBase64'
+import base64Decode from 'fast-base64-decode'
 
 class TypeMismatchError extends Error {}
 class QuotaExceededError extends Error {}
@@ -31,7 +31,7 @@ function getRandomValues (array) {
     throw new QuotaExceededError('Can only request a maximum of 65536 bytes')
   }
 
-  // Calling RNGetRandomValues.getRandomBase64 in debug mode leads to the error
+  // Calling getRandomBase64 in debug mode leads to the error
   // "Calling synchronous methods on native modules is not supported in Chrome".
   // So in that specific case we fall back to just using Math.random.
   if (__DEV__) {
@@ -40,7 +40,7 @@ function getRandomValues (array) {
     }
   }
 
-  base64Decode(RNGetRandomValues.getRandomBase64(array.byteLength), new Uint8Array(array.buffer, array.byteOffset, array.byteLength))
+  base64Decode(getRandomBase64(array.byteLength), new Uint8Array(array.buffer, array.byteOffset, array.byteLength))
 
   return array
 }

readme.md

@@ -1,14 +1,16 @@
-# `getRandomValues` for React Native
+# `crypo.getRandomValues` for React Native
 
-A small implementation of `getRandomValues` for React Native.
+A small implementation of `crypto.getRandomValues` for React Native. This is useful to polyfill for libraries like [uuid](https://www.npmjs.com/package/uuid) that depend on it.
 
 ## Installation
 
 ```sh
 npm install --save react-native-get-random-values
-cd ios && pod install && cd ..
+npx pod-install
 ```
 
+> 💡 If you use the Expo managed workflow you will see "CocoaPods is not supported in this project" - this is fine, it's not necessary.
+
 ## Usage
 
 This library works as a polyfill for the global `crypto.getRandomValues`.
@@ -18,6 +20,13 @@ This library works as a polyfill for the global `crypto.getRandomValues`.
 import 'react-native-get-random-values'
 ```
 
+Now you can use `uuid` or other libraries that assume `crypto.getRandomValues` is available.
+
+```javascript
+import { v4 as uuid } from 'uuid';
+console.log(uuid());
+```
+
 ## API
 
 ### `crypto.getRandomValues(typedArray)`