Fix base64 in browser

lib/util/base64.ts

@@ -19,7 +19,11 @@ export function encodeString(value: string): string {
  */
 export function encodeByteArray(value: Uint8Array): string {
   if (typeof Buffer === "undefined") {
-    return btoa(encodeURIComponent(new TextDecoder().decode(value)));
+    let str = "";
+    for (let i = 0; i < value.length; i++) {
+      str += String.fromCharCode(value[i]);
+    }
+    return btoa(str);
   } else {
     // Buffer.from accepts <ArrayBuffer> | <SharedArrayBuffer>-- the TypeScript definition is off here
     // https://nodejs.org/api/buffer.html#buffer_class_method_buffer_from_arraybuffer_byteoffset_length
@@ -34,7 +38,12 @@ export function encodeByteArray(value: Uint8Array): string {
  */
 export function decodeString(value: string): Uint8Array {
   if (typeof Buffer === "undefined") {
-    return new TextEncoder().encode(atob(value));
+    const byteString = atob(value);
+    const arr = new Uint8Array(byteString.length);
+    for (let i = 0; i < byteString.length; i++) {
+      arr[i] = byteString.charCodeAt(i);
+    }
+    return arr;
   } else {
     return Buffer.from(value, "base64");
   }

test/shared/serializationTests.ts

@@ -772,7 +772,7 @@ describe("msrest", function () {
         "birthday": new Date("2012-01-05T01:00:00Z").toISOString(),
         "species": "king",
         "length": 1.0,
-        "picture": Uint8Array.from([255, 255, 255, 255, 254]).toString(),
+        "picture": "/////g==",
         "siblings": [
           {
             "fish.type": "shark",
@@ -786,7 +786,7 @@ describe("msrest", function () {
             "age": 105,
             "birthday": new Date("1900-01-05T01:00:00Z").toISOString(),
             "length": 10.0,
-            "picture": Uint8Array.from([255, 255, 255, 255, 254]).toString(),
+            "picture": "/////g==",
             "species": "dangerous"
           }
         ]
@@ -873,14 +873,14 @@ describe("msrest", function () {
         'birthday': new Date('2012-01-05T01:00:00Z').toISOString(),
         'species': 'king',
         'length': 1.0,
-        'picture': Uint8Array.from([255, 255, 255, 255, 254]).toString(),
+        'picture': "/////g==",
         'siblings': [
           {
             'fish.type': 'mutatedshark',
             'age': 105,
             'birthday': new Date('1900-01-05T01:00:00Z').toISOString(),
             'length': 10.0,
-            'picture': Uint8Array.from([255, 255, 255, 255, 254]).toString(),
+            'picture': "/////g==",
             'species': 'dangerous',
             'siblings': [
               {