Not implemented error with react native

CHANGELOG.md

@@ -285,4 +285,5 @@ Released with 1.0.0-beta.37 code base.
 ### Fixed
 
 - Fix parsing of non-`eth_subscription` provider events (#3660)
-- Fix return value for `clearSubscriptions` (#3689)
+- Fix parsedUrl problem of websocket provider (#3666)
+- Fix return value for `clearSubscriptions` (#3689)

packages/web3-providers-ws/src/helpers.js

@@ -1,8 +1,9 @@
 var isNode = Object.prototype.toString.call(typeof process !== 'undefined' ? process : 0) === '[object process]';
+var isRN = typeof navigator !== 'undefined' && navigator.product === 'ReactNative';
 
 var _btoa = null;
 var helpers = null;
-if (isNode) {
+if (isNode || isRN) {
     _btoa = function(str) {
         return Buffer.from(str).toString('base64');
     };