#2 - Fix user can submit 10-digit amount and gives an unexpected error

src/CONST.ts

@@ -1580,7 +1580,7 @@ const CONST = {
             APPROVE: 'approve',
             TRACK: 'track',
         },
-        AMOUNT_MAX_LENGTH: 10,
+        AMOUNT_MAX_LENGTH: 8,
         RECEIPT_STATE: {
             SCANREADY: 'SCANREADY',
             OPEN: 'OPEN',

src/libs/MoneyRequestUtils.ts

@@ -37,31 +37,16 @@ function addLeadingZero(amount: string): string {
     return amount.startsWith('.') ? `0${amount}` : amount;
 }
 
-/**
- * Calculate the length of the amount with leading zeroes
- */
-function calculateAmountLength(amount: string, decimals: number): number {
-    const leadingZeroes = amount.match(/^0+/);
-    const leadingZeroesLength = leadingZeroes?.[0]?.length ?? 0;
-    const absAmount = parseFloat((Number(stripCommaFromAmount(amount)) * 10 ** decimals).toFixed(2)).toString();
-
-    if (/\D/.test(absAmount)) {
-        return CONST.IOU.AMOUNT_MAX_LENGTH + 1;
-    }
-
-    return leadingZeroesLength + (absAmount === '0' ? 2 : absAmount.length);
-}
-
 /**
  * Check if amount is a decimal up to 3 digits
  */
 function validateAmount(amount: string, decimals: number, amountMaxLength: number = CONST.IOU.AMOUNT_MAX_LENGTH): boolean {
     const regexString =
         decimals === 0
-            ? `^\\d+(,\\d*)*$` // Don't allow decimal point if decimals === 0
-            : `^\\d+(,\\d*)*(\\.\\d{0,${decimals}})?$`; // Allow the decimal point and the desired number of digits after the point
+            ? `^\\d{1,${amountMaxLength}}$` // Don't allow decimal point if decimals === 0
+            : `^\\d{1,${amountMaxLength}}(\\.\\d{0,${decimals}})?$`; // Allow the decimal point and the desired number of digits after the point
     const decimalNumberRegex = new RegExp(regexString, 'i');
-    return amount === '' || (decimalNumberRegex.test(amount) && calculateAmountLength(amount, decimals) <= amountMaxLength);
+    return amount === '' || decimalNumberRegex.test(amount);
 }
 
 /**

src/pages/workspace/taxes/ValuePage.tsx

@@ -89,7 +89,7 @@ function ValuePage({
                         // The default currency uses 2 decimal places, so we substract it
                         extraDecimals={CONST.MAX_TAX_RATE_DECIMAL_PLACES - 2}
                         // We increase the amount max length to support the extra decimals.
-                        amountMaxLength={CONST.MAX_TAX_RATE_DECIMAL_PLACES + CONST.MAX_TAX_RATE_INTEGER_PLACES}
+                        amountMaxLength={CONST.MAX_TAX_RATE_INTEGER_PLACES}
                         extraSymbol={<Text style={styles.iouAmountText}>%</Text>}
                         ref={inputCallbackRef}
                     />

src/pages/workspace/taxes/WorkspaceCreateTaxPage.tsx

@@ -108,7 +108,7 @@ function WorkspaceCreateTaxPage({
                                     // The default currency uses 2 decimal places, so we substract it
                                     extraDecimals={CONST.MAX_TAX_RATE_DECIMAL_PLACES - 2}
                                     // We increase the amount max length to support the extra decimals.
-                                    amountMaxLength={CONST.MAX_TAX_RATE_DECIMAL_PLACES + CONST.MAX_TAX_RATE_INTEGER_PLACES}
+                                    amountMaxLength={CONST.MAX_TAX_RATE_INTEGER_PLACES}
                                     extraSymbol={<Text style={styles.iouAmountText}>%</Text>}
                                 />
                             </View>

tests/unit/MoneyRequestUtilsTest.ts

@@ -0,0 +1,22 @@
+import * as MoneyRequestUtils from '@libs/MoneyRequestUtils';
+
+describe('ReportActionsUtils', () => {
+    describe('validateAmount', () => {
+        it('should pass the validation when amount is within the max digit and decimal', () => {
+            expect(MoneyRequestUtils.validateAmount('12345678', 2, 8)).toBe(true);
+            expect(MoneyRequestUtils.validateAmount('12345678', 0, 8)).toBe(true);
+            expect(MoneyRequestUtils.validateAmount('12345678.12', 2, 8)).toBe(true);
+            expect(MoneyRequestUtils.validateAmount('1234567.1', 2, 8)).toBe(true);
+            expect(MoneyRequestUtils.validateAmount('12345678.123', 3, 8)).toBe(true);
+            expect(MoneyRequestUtils.validateAmount('1234.1234', 4, 4)).toBe(true);
+        });
+
+        it("shouldn't pass the validation when amount is bigger than the max digit and decimal", () => {
+            expect(MoneyRequestUtils.validateAmount('12345678.123', 2, 8)).toBe(false);
+            expect(MoneyRequestUtils.validateAmount('12345678.1', 0, 8)).toBe(false);
+            expect(MoneyRequestUtils.validateAmount('123456789.12', 2, 8)).toBe(false);
+            expect(MoneyRequestUtils.validateAmount('123456789.1234', 3, 8)).toBe(false);
+            expect(MoneyRequestUtils.validateAmount('1234.12345', 4, 4)).toBe(false);
+        });
+    });
+});