chore(FE-188,193): create formik helper function utils and create removeArrayItemAndSync formik helper function

src/lib/utils/formik.ts

@@ -0,0 +1,48 @@
+import { FormikContextType, getIn, setIn } from 'formik';
+
+function spliceArray<T>(arr: T[] | undefined, index: number) {
+  const a = Array.isArray(arr) ? arr.slice() : [];
+  if (index >= 0 && index < a.length) a.splice(index, 1);
+  return a;
+}
+
+/**
+ * Remove one item from an array field and also trim Formik's errors & touched
+ * at the SAME index to keep everything aligned.
+ *
+ * @param formik - your useFormik instance
+ * @param arrayPath - path to the array field, e.g. "kandangExpenses[0].expenses"
+ * @param index - the index to remove
+ * @param validateAfter - optional: revalidate after removal (default false)
+ */
+export async function removeArrayItemAndSync<FormValues>(
+  formik: FormikContextType<FormValues>,
+  arrayPath: string,
+  index: number,
+  validateAfter: boolean = false
+) {
+  // 1) VALUES: remove at index
+  const currValues = getIn(formik.values, arrayPath);
+  const nextValues = spliceArray(currValues, index);
+  formik.setFieldValue(arrayPath, nextValues, false);
+
+  // 2) ERRORS: remove the same index (if array exists)
+  const currErrors = getIn(formik.errors, arrayPath);
+  if (Array.isArray(currErrors)) {
+    const nextErrors = spliceArray(currErrors, index);
+    formik.setErrors(setIn(formik.errors, arrayPath, nextErrors));
+  }
+
+  // 3) TOUCHED: remove the same index (if array exists)
+  const currTouched = getIn(formik.touched, arrayPath);
+  if (Array.isArray(currTouched)) {
+    const nextTouched = spliceArray(currTouched, index);
+    formik.setTouched(setIn(formik.touched, arrayPath, nextTouched), false);
+  }
+
+  // 4) (optional) revalidate to rebuild a perfectly clean error tree
+  if (validateAfter) {
+    const newErrors = await formik.validateForm();
+    formik.setErrors(newErrors);
+  }
+}