fix: confirmation modal does not change the transaction in the edit f…

…ields

frontend/src/pages/dashboard/prepare-submit.test.ts

@@ -0,0 +1,35 @@
+import { Posting } from 'pta-tools';
+
+import prepareSubmit from './prepare-submit';
+
+import { FormData, OPTION_SPLITWISE } from './';
+
+describe("prepareSubmit", () => {
+  test("Does not mutate the input trx", () => {
+    const trx: FormData = {
+      comment: "comment",
+      date: new Date("2019-01-01"),
+      description: "string",
+      entries: [{ account: "Bar", amount: "7" }],
+      payingAccount: "Cash",
+    };
+
+    expect(prepareSubmit(trx, []).entries.length).toBe(2);
+    expect(trx.entries.length).toBe(1); // trx.entries is not mutated
+  });
+  test("Splits with Splitwise", () => {
+    const trx: FormData = {
+      comment: "comment",
+      date: new Date("2019-01-01"),
+      description: "string",
+      entries: [{ account: "Bar", amount: "7" }],
+      payingAccount: "Cash",
+    };
+
+    const result = prepareSubmit(trx, [OPTION_SPLITWISE]);
+    expect(result.entries.length).toBe(3);
+    expect((result.entries[0] as Posting).amount).toBe("3.5");
+    expect((result.entries[1] as Posting).amount).toBe("3.5");
+    expect((result.entries[2] as Posting).account).toBe("Cash");
+  });
+});

frontend/src/pages/dashboard/prepare-submit.ts

@@ -31,7 +31,9 @@ function prepareSubmitData(data: FormData, options: string[]): Transaction {
   }
 
   if (payingAccount) {
-    transaction.entries.push({ account: payingAccount });
+    transaction.entries = transaction.entries.concat({
+      account: payingAccount,
+    });
   }
   return transaction;
 }