Normalize odometer input to reject non-numeric characters

src/libs/DistanceRequestUtils.ts

@@ -474,12 +474,25 @@ function isDistanceAmountWithinLimit(distance: number, rate: number): boolean {
  * Normalize odometer text by standardizing locale digits and stripping all
  * non-numeric characters except the decimal point. fromLocaleDigit converts
  * each locale character to its standard equivalent (e.g. German ',' → '.'
- * for decimal, German '.' → ',' for group separator), then we keep only
- * digits and the standard decimal point.
+ * for decimal, German '.' → ',' for group separator), so after conversion
+ * dots are always decimals and commas are always group separators.
+ * We then strip everything except digits and the standard decimal point.
  */
 function normalizeOdometerText(text: string, fromLocaleDigit: (char: string) => string): string {
     const standardized = replaceAllDigits(text, fromLocaleDigit);
-    return standardized.replaceAll(/[^0-9.]/g, '');
+    const stripped = standardized.replaceAll(/[^0-9.]/g, '');
+    // Remove redundant leading zeroes (e.g. "007" → "7", "000" → "0") but
+    // keep a single zero before a decimal point (e.g. "0.5" stays "0.5").
+    return stripped.replace(/^0+(?=\d)/, '');
+}
+
+/**
+ * Prepare odometer input text for display by removing non-numeric characters
+ * (except the decimal point, comma, and space — which serve as group or
+ * decimal separators depending on locale) and stripping redundant leading zeroes.
+ */
+function prepareTextForDisplay(text: string): string {
+    return text.replaceAll(/[^0-9., ]/g, '').replace(/^0+(?=\d)/, '');
 }
 
 export default {
@@ -503,6 +516,7 @@ export default {
     getRateForExpenseDisplay,
     isDistanceAmountWithinLimit,
     normalizeOdometerText,
+    prepareTextForDisplay,
 };
 
 export type {MileageRate};

src/pages/iou/request/step/IOURequestStepDistanceOdometer.tsx

@@ -308,8 +308,9 @@ function IOURequestStepDistanceOdometer({
         if (!isOdometerInputValid(text, startReading)) {
             return;
         }
-        setStartReading(text);
-        startReadingRef.current = text;
+        const textForDisplay = DistanceRequestUtils.prepareTextForDisplay(text);
+        setStartReading(textForDisplay);
+        startReadingRef.current = textForDisplay;
         if (formError) {
             setFormError('');
         }
@@ -319,8 +320,9 @@ function IOURequestStepDistanceOdometer({
         if (!isOdometerInputValid(text, endReading)) {
             return;
         }
-        setEndReading(text);
-        endReadingRef.current = text;
+        const textForDisplay = DistanceRequestUtils.prepareTextForDisplay(text);
+        setEndReading(textForDisplay);
+        endReadingRef.current = textForDisplay;
         if (formError) {
             setFormError('');
         }

tests/unit/OdometerNormalizationTest.ts

@@ -9,7 +9,7 @@ describe('normalizeOdometerText', () => {
             expect(DistanceRequestUtils.normalizeOdometerText('1,5', germanFromLocaleDigit)).toBe('1.5');
         });
 
-        it("German '1.5' (fifteen, dot is group separator) normalizes to '15'", () => {
+        it("German '1.5' (dot is group separator, fifteen) normalizes to '15'", () => {
             expect(DistanceRequestUtils.normalizeOdometerText('1.5', germanFromLocaleDigit)).toBe('15');
         });
 
@@ -37,4 +37,104 @@ describe('normalizeOdometerText', () => {
             expect(DistanceRequestUtils.normalizeOdometerText('9999999', englishFromLocaleDigit)).toBe('9999999');
         });
     });
+
+    describe('locale-strict decimal handling', () => {
+        const englishFromLocaleDigit = (char: string) => fromLocaleDigit('en', char);
+        const germanFromLocaleDigit = (char: string) => fromLocaleDigit('de', char);
+
+        it("English '123,4' (comma is group separator, not decimal) normalizes to '1234'", () => {
+            expect(DistanceRequestUtils.normalizeOdometerText('123,4', englishFromLocaleDigit)).toBe('1234');
+        });
+
+        it("English '1,234.5' (comma as group with dot decimal) normalizes to '1234.5'", () => {
+            expect(DistanceRequestUtils.normalizeOdometerText('1,234.5', englishFromLocaleDigit)).toBe('1234.5');
+        });
+
+        it("German '1.234,5' (dot-group, comma-decimal) normalizes to '1234.5'", () => {
+            expect(DistanceRequestUtils.normalizeOdometerText('1.234,5', germanFromLocaleDigit)).toBe('1234.5');
+        });
+
+        it("plain comma with identity function: ',5' normalizes to '5' (comma stripped)", () => {
+            const identity = (char: string) => char;
+            expect(DistanceRequestUtils.normalizeOdometerText(',5', identity)).toBe('5');
+        });
+    });
+
+    describe('leading zeroes', () => {
+        const identity = (char: string) => char;
+
+        it("strips redundant leading zeroes: '000' → '0'", () => {
+            expect(DistanceRequestUtils.normalizeOdometerText('000', identity)).toBe('0');
+        });
+
+        it("strips leading zeroes before digits: '007' → '7'", () => {
+            expect(DistanceRequestUtils.normalizeOdometerText('007', identity)).toBe('7');
+        });
+
+        it("keeps single zero before decimal: '0.5' → '0.5'", () => {
+            expect(DistanceRequestUtils.normalizeOdometerText('0.5', identity)).toBe('0.5');
+        });
+
+        it("normalizes multiple zeroes before decimal: '00.5' → '0.5'", () => {
+            expect(DistanceRequestUtils.normalizeOdometerText('00.5', identity)).toBe('0.5');
+        });
+
+        it("keeps a single zero: '0' → '0'", () => {
+            expect(DistanceRequestUtils.normalizeOdometerText('0', identity)).toBe('0');
+        });
+
+        it("does not affect numbers without leading zeroes: '123' → '123'", () => {
+            expect(DistanceRequestUtils.normalizeOdometerText('123', identity)).toBe('123');
+        });
+    });
+});
+
+describe('prepareTextForDisplay', () => {
+    it("strips non-numeric characters except decimal and comma: 'abc123.4def' → '123.4'", () => {
+        expect(DistanceRequestUtils.prepareTextForDisplay('abc123.4def')).toBe('123.4');
+    });
+
+    it("keeps commas for locale display: '1,234.5' → '1,234.5'", () => {
+        expect(DistanceRequestUtils.prepareTextForDisplay('1,234.5')).toBe('1,234.5');
+    });
+
+    it("strips leading zeroes: '007' → '7'", () => {
+        expect(DistanceRequestUtils.prepareTextForDisplay('007')).toBe('7');
+    });
+
+    it("strips redundant leading zeroes: '000' → '0'", () => {
+        expect(DistanceRequestUtils.prepareTextForDisplay('000')).toBe('0');
+    });
+
+    it("keeps single zero before decimal: '0.5' → '0.5'", () => {
+        expect(DistanceRequestUtils.prepareTextForDisplay('0.5')).toBe('0.5');
+    });
+
+    it("normalizes multiple leading zeroes before decimal: '00.5' → '0.5'", () => {
+        expect(DistanceRequestUtils.prepareTextForDisplay('00.5')).toBe('0.5');
+    });
+
+    it("keeps single zero: '0' → '0'", () => {
+        expect(DistanceRequestUtils.prepareTextForDisplay('0')).toBe('0');
+    });
+
+    it("strips letters and symbols: '@#$%123' → '123'", () => {
+        expect(DistanceRequestUtils.prepareTextForDisplay('@#$%123')).toBe('123');
+    });
+
+    it("handles empty string: '' → ''", () => {
+        expect(DistanceRequestUtils.prepareTextForDisplay('')).toBe('');
+    });
+
+    it("handles valid number unchanged: '12345.6' → '12345.6'", () => {
+        expect(DistanceRequestUtils.prepareTextForDisplay('12345.6')).toBe('12345.6');
+    });
+
+    it("keeps spaces as group separator (French locale): '1 234,5' → '1 234,5'", () => {
+        expect(DistanceRequestUtils.prepareTextForDisplay('1 234,5')).toBe('1 234,5');
+    });
+
+    it("keeps periods as group separator (Italian locale): '1.234,5' → '1.234,5'", () => {
+        expect(DistanceRequestUtils.prepareTextForDisplay('1.234,5')).toBe('1.234,5');
+    });
 });