(Bug Fix) isDate function: Add validation for delimiter and length ch…

…ecks to prevent undefined errors

src/lib/isDate.js

@@ -1,13 +1,15 @@
-import merge from './util/merge';
+import merge from "./util/merge";
 
 const default_date_options = {
-  format: 'YYYY/MM/DD',
-  delimiters: ['/', '-'],
+  format: "YYYY/MM/DD",
+  delimiters: ["/", "-"],
   strictMode: false,
 };
 
 function isValidFormat(format) {
-  return /(^(y{4}|y{2})[.\/-](m{1,2})[.\/-](d{1,2})$)|(^(m{1,2})[.\/-](d{1,2})[.\/-]((y{4}|y{2})$))|(^(d{1,2})[.\/-](m{1,2})[.\/-]((y{4}|y{2})$))/gi.test(format);
+  return /(^(y{4}|y{2})[.\/-](m{1,2})[.\/-](d{1,2})$)|(^(m{1,2})[.\/-](d{1,2})[.\/-]((y{4}|y{2})$))|(^(d{1,2})[.\/-](m{1,2})[.\/-]((y{4}|y{2})$))/gi.test(
+    format
+  );
 }
 
 function zip(date, format) {
@@ -22,21 +24,38 @@ function zip(date, format) {
 }
 
 export default function isDate(input, options) {
-  if (typeof options === 'string') { // Allow backward compatibility for old format isDate(input [, format])
+  if (typeof options === "string") {
+    // Allow backward compatibility for old format isDate(input [, format])
     options = merge({ format: options }, default_date_options);
   } else {
     options = merge(options, default_date_options);
   }
-  if (typeof input === 'string' && isValidFormat(options.format)) {
-    const formatDelimiter = options.delimiters
-      .find(delimiter => options.format.indexOf(delimiter) !== -1);
+  if (typeof input === "string" && isValidFormat(options.format)) {
+    // Ensure the input contains at least one valid delimiter
+    const hasValidDelimiter = options.delimiters.some((delimiter) =>
+      input.includes(delimiter)
+    );
+    if (!hasValidDelimiter) {
+      return false;
+    }
+
+    const formatDelimiter = options.delimiters.find(
+      (delimiter) => options.format.indexOf(delimiter) !== -1
+    );
     const dateDelimiter = options.strictMode
       ? formatDelimiter
-      : options.delimiters.find(delimiter => input.indexOf(delimiter) !== -1);
-    const dateAndFormat = zip(
-      input.split(dateDelimiter),
-      options.format.toLowerCase().split(formatDelimiter)
-    );
+      : options.delimiters.find((delimiter) => input.indexOf(delimiter) !== -1);
+
+    // Split input and format by the delimiters
+    const inputParts = input.split(dateDelimiter);
+    const formatParts = options.format.toLowerCase().split(formatDelimiter);
+
+    // Check if splitting produced the same number of parts
+    if (inputParts.length !== formatParts.length) {
+      return false;
+    }
+
+    const dateAndFormat = zip(inputParts, formatParts);
     const dateObj = {};
 
     for (const [dateWord, formatWord] of dateAndFormat) {
@@ -50,7 +69,7 @@ export default function isDate(input, options) {
     let fullYear = dateObj.y;
 
     // Check if the year starts with a hyphen
-    if (fullYear.startsWith('-')) {
+    if (fullYear.startsWith("-")) {
       return false; // Hyphen before year is not allowed
     }
 
@@ -82,11 +101,16 @@ export default function isDate(input, options) {
       day = `0${dateObj.d}`;
     }
 
-    return new Date(`${fullYear}-${month}-${day}T00:00:00.000Z`).getUTCDate() === +dateObj.d;
+    // Construct a date string in the format YYYY-MM-DD and validate
+    const parsedDate = new Date(`${fullYear}-${month}-${day}T00:00:00.000Z`);
+    return parsedDate.getUTCDate() === +dateObj.d; // Check if the day matches
   }
 
   if (!options.strictMode) {
-    return Object.prototype.toString.call(input) === '[object Date]' && isFinite(input);
+    return (
+      Object.prototype.toString.call(input) === "[object Date]" &&
+      isFinite(input)
+    );
   }
 
   return false;