AES256GCM decrypt: replace Observable with Promise

packages/wallet-sdk/src/relay/WalletSDKRelay.ts

@@ -3,7 +3,7 @@
 
 import bind from "bind-decorator";
 import { ethErrors } from "eth-rpc-errors";
-import { BehaviorSubject, Observable, of, Subscription, zip } from "rxjs";
+import { BehaviorSubject, from, Observable, of, Subscription, zip } from "rxjs";
 import {
   catchError,
   distinctUntilChanged,
@@ -777,8 +777,7 @@ export class WalletSDKRelay extends WalletSDKRelayAbstract {
   private handleIncomingEvent(event: ServerMessageEvent): void {
     try {
       this.subscriptions.add(
-        aes256gcm
-          .decrypt(event.data, this.session.secret)
+        from(aes256gcm.decrypt(event.data, this.session.secret))
           .pipe(map(c => JSON.parse(c)))
           .subscribe({
             next: json => {

packages/wallet-sdk/src/relay/aes256gcm.test.ts

@@ -12,14 +12,12 @@ describe("aes256gcm", () => {
     expect(encrypted.length).toEqual(90);
 
     // decrypted output matches original input
-    decrypt(encrypted, randSecret).subscribe({
-      next: decrypted => {
-        expect(decrypted).toBe("plain text string");
-      },
-    });
+    const decrypted = await decrypt(encrypted, randSecret);
+
+    expect(decrypted).toBe("plain text string");
   });
 
-  test("decrypt", () => {
+  test("decrypt", async () => {
     const cipherText =
       "06593325a922a928913b5c6ea26f848c4545bcea4e26c4f5ee745316ff22b2780aeccc565730514b2820a94b03f5f89fe7542a35bbdd87a1d52a4352f49482781113db09266c668696778e0a94bc9f866f1e92e7262fd0bb811838284cc64cbc4552b33e9c6fb2582cea4f49471d6d46a16a5c8ac83ee8483ed4dc01f1fde3bfd7a2f173715e0a8d09dd4907483f096a845bff698831ea277c1ca4223d3f6073174cb35119d0a795c1a9cb4f32ee1dcc254d8931";
     const sampleDataResult = {
@@ -31,11 +29,9 @@ describe("aes256gcm", () => {
       },
     };
 
-    decrypt(cipherText, secret).subscribe({
-      next: value => {
-        expect(sampleDataResult).toEqual(value);
-      },
-    });
+    const decrypted = await decrypt(cipherText, secret);
+
+    expect(sampleDataResult).toEqual(JSON.parse(decrypted));
   });
 
   test("errors", async () => {
@@ -47,15 +43,6 @@ describe("aes256gcm", () => {
       "secret must be 256 bits",
     );
 
-    await expect(
-      decrypt("text", secret).subscribe(
-        () => {
-          fail("expected error");
-        },
-        error => {
-          expect(error).toBe("expected error");
-        },
-      ),
-    );
+    await expect(decrypt("text", secret)).rejects.toThrow();
   });
 });

packages/wallet-sdk/src/relay/aes256gcm.ts

@@ -1,8 +1,6 @@
 // Copyright (c) 2018-2022 Coinbase, Inc. <https://www.coinbase.com/>
 // Licensed under the Apache License, version 2.0
 
-import { Observable } from "rxjs";
-
 import { hexStringToUint8Array, uint8ArrayToHex } from "../util";
 
 /**
@@ -63,15 +61,10 @@ export async function encrypt(
  * @param cipherText hex string representation of bytes in the order: initialization vector (iv),
  * auth tag, encrypted plaintext. IV is 12 bytes. Auth tag is 16 bytes.
  * @param secret hex string representation of 32-byte secret
- *
- * TODO: Update rxjs for promises
  */
-export function decrypt(
-  cipherText: string,
-  secret: string,
-): Observable<string> {
+export function decrypt(cipherText: string, secret: string): Promise<string> {
   if (secret.length !== 64) throw Error(`secret must be 256 bits`);
-  return new Observable<string>(subscriber => {
+  return new Promise<string>((resolve, reject) => {
     void (async function () {
       const secretKey: CryptoKey = await crypto.subtle.importKey(
         "raw",
@@ -101,10 +94,9 @@ export function decrypt(
           concattedBytes,
         );
         const decoder = new TextDecoder();
-        subscriber.next(decoder.decode(decrypted));
-        subscriber.complete();
+        resolve(decoder.decode(decrypted));
       } catch (err) {
-        subscriber.error(err);
+        reject(err);
       }
     })();
   });