feat: 优化

utils/def.js

@@ -0,0 +1,12 @@
+module.exports.isDef = function isDef(v) {
+  return v !== undefined && v !== null;
+};
+
+module.exports.isUnDef = function isUnDef(v) {
+  return v === undefined || v === null;
+};
+
+module.exports.isDate = function isDate(d) {
+  const D = new Date(d);
+  return !D.toString().includes('Invalid');
+};