util: fix payto URI construction

3 files changed, 25 insertions, 3 deletions

diff --git a/packages/taler-util/src/payto.test.ts b/packages/taler-util/src/payto.test.ts
index 1b6907cbb..3b28c4714 100644
--- a/packages/taler-util/src/payto.test.ts
+++ b/packages/taler-util/src/payto.test.ts
@@ -16,7 +16,7 @@
 
 import test from "ava";
 
-import { PaytoString, parsePaytoUri, stringifyPaytoUri } from "./payto.js";
+import { PaytoString, addPaytoQueryParams, parsePaytoUri, stringifyPaytoUri } from "./payto.js";
 
 test("basic payto parsing", (t) => {
   const r1 = parsePaytoUri("https://example.com/");
@@ -42,3 +42,15 @@ test("parsing payto with % carh", (t) => {
 
   t.is(stringifyPaytoUri(parsePaytoUri(payto1)!), payto1);
 });
+
+test("adding payto query params", (t) => {
+  const payto1 =
+    "payto://iban/DE1231231231?receiver-name=John%20Doe" as PaytoString;
+  const out1 = addPaytoQueryParams(payto1, {});
+  t.deepEqual(payto1, out1);
+
+  const out2 = addPaytoQueryParams(payto1, {
+    foo: "42",
+  });
+  t.deepEqual(out2, "payto://iban/DE1231231231?receiver-name=John%20Doe&foo=42");
+});
diff --git a/packages/taler-util/src/payto.ts b/packages/taler-util/src/payto.ts
index cd90de3a4..3a332b37e 100644
--- a/packages/taler-util/src/payto.ts
+++ b/packages/taler-util/src/payto.ts
@@ -160,14 +160,20 @@ export function buildPayto(
 }
 
 /**
- * Add query parameters to a payto URI
+ * Add query parameters to a payto URI.
+ *
+ * Existing parameters are preserved.
  */
 export function addPaytoQueryParams(
   s: string,
   params: { [name: string]: string },
 ): string {
   const [acct, search] = s.slice(paytoPfx.length).split("?");
-  const paramList = !params ? [] : Object.entries(params);
+  const searchParams = new URLSearchParams(search || "");
+  for (const [paramKey, paramValue] of Object.entries(params)) {
+    searchParams.set(paramKey, paramValue);
+  }
+  const paramList = [...searchParams.entries()];
   if (paramList.length === 0) {
     return paytoPfx + acct;
   }
diff --git a/packages/taler-util/src/whatwg-url.ts b/packages/taler-util/src/whatwg-url.ts
index 13abf5397..869b304ed 100644
--- a/packages/taler-util/src/whatwg-url.ts
+++ b/packages/taler-util/src/whatwg-url.ts
@@ -424,6 +424,10 @@ export class URLSearchParamsImpl {
     return output;
   }
 
+  entries() {
+    return [...this._list.map(x => [x[0], x[1]])];
+  }
+
   forEach(
     callbackfn: (
       value: string,