use custom encoder to allow + in password

angular-oauth2-oidc/src/encoder.ts

@@ -0,0 +1,21 @@
+import {HttpParameterCodec} from '@angular/common/http';
+/**
+ * This custom encoder allows charactes like +, % and / to be used in passwords
+ */
+export class WebHttpUrlEncodingCodec implements HttpParameterCodec {
+    encodeKey(k: string): string {
+        return encodeURIComponent(k);
+    }
+
+    encodeValue(v: string): string {
+        return encodeURIComponent(v);
+    }
+
+    decodeKey(k: string): string {
+        return decodeURIComponent(k);
+    }
+
+    decodeValue(v: string) {
+        return decodeURIComponent(v);
+    }
+}

angular-oauth2-oidc/src/oauth-service.ts

@@ -10,6 +10,7 @@ import { OAuthEvent, OAuthInfoEvent, OAuthErrorEvent, OAuthSuccessEvent } from '
 import { OAuthStorage, LoginOptions, ParsedIdToken, OidcDiscoveryDoc, TokenResponse, UserInfo } from './types';
 import { b64DecodeUnicode } from './base64-helper';
 import { AuthConfig } from './auth.config';
+import { WebHttpUrlEncodingCodec } from './encoder';
 
 /**
  * Service for logging in and logging out with
@@ -554,7 +555,13 @@ export class OAuthService
         }
 
         return new Promise((resolve, reject) => {
-            let params = new HttpParams()
+            /**
+             * A `HttpParameterCodec` that uses `encodeURIComponent` and `decodeURIComponent` to
+             * serialize and parse URL parameter keys and values.
+             *
+             * @stable
+             */
+            let params = new HttpParams({encoder: new WebHttpUrlEncodingCodec() })
                 .set('grant_type', 'password')
                 .set('client_id', this.clientId)
                 .set('scope', this.scope)