[improvement] optimize isNaN (#3988)

src/datetime-picker/utils.ts

@@ -0,0 +1,28 @@
+import { isNaN } from '../utils/validate/number';
+
+export function times(n: number, iteratee: (index: number) => any[]) {
+  let index = -1;
+  const result = Array(n);
+
+  while (++index < n) {
+    result[index] = iteratee(index);
+  }
+
+  return result;
+}
+
+export function getTrueValue(value: string | undefined): number | undefined {
+  if (!value) {
+    return;
+  }
+
+  while (isNaN(parseInt(value, 10))) {
+    value = value.slice(1);
+  }
+
+  return parseInt(value, 10);
+}
+
+export function getMonthEndDay(year: number, month: number): number {
+  return 32 - new Date(year, month - 1, 32).getDate();
+}