lib: clear in-memory credentials after connection

Author: jamaljsr

lib/lnc.ts

@@ -229,6 +229,12 @@ export default class LNC {
                     clearInterval(interval);
                     resolve();
                     log.info('The WASM client is connected to the server');
+
+                    // clear the in-memory credentials after connecting if the
+                    // credentials are persisted in local storage
+                    if (this.credentials.password) {
+                        this.credentials.clear(true);
+                    }
                 } else if (counter > 20) {
                     clearInterval(interval);
                     reject(

lib/types/lnc.ts

@@ -132,6 +132,11 @@ export interface CredentialStore {
      * credentials persisted in the store
      */
     isPaired: boolean;
-    /** Clears any persisted data in the store */
-    clear(): void;
+    /**
+     * Clears the in-memory and persisted data in the store.
+     * @param memoryOnly If `true`, only the in-memory data will be cleared. If
+     * `false` or `undefined`, the persisted data will be cleared as well.
+     * The default is `undefined`.
+     */
+    clear(memoryOnly?: boolean): void;
 }

lib/util/credentialStore.ts

@@ -105,6 +105,10 @@ export default class LncCredentialStore implements CredentialStore {
             if (this.remoteKey)
                 this.persisted.remoteKey = this._encrypt(this.remoteKey);
             this._save();
+
+            // once the encrypted data is persisted, we can clear the plain text
+            // credentials from memory
+            this.clear(true);
         }
     }
 
@@ -170,9 +174,11 @@ export default class LncCredentialStore implements CredentialStore {
     }
 
     /** Clears any persisted data in the store */
-    clear() {
-        const key = `${STORAGE_KEY}:${this.namespace}`;
-        localStorage.removeItem(key);
+    clear(memoryOnly?: boolean) {
+        if (!memoryOnly) {
+            const key = `${STORAGE_KEY}:${this.namespace}`;
+            localStorage.removeItem(key);
+        }
         this.persisted = {
             salt: '',
             cipher: '',