How to Check Whether an Object is a Date

In this tutorial, we suggest several methods of checking whether the parameter passed to the method is of type Date or not.

There is a workable and probably the best solution that checks the object's class:

Object.prototype.toString.call(input) === '[object Date]'

Example:

javascript— editable

There are also some other methods. One of them is using the instanceof operator, like this:

date instanceof Date

Example:

javascript— editable

Warning

However, it will return true for invalid dates too, for example, new Date('random_string') is also an instance of Date. This will fail if objects are passed across frame boundaries.

There is another solution that suggests checking if the object has a getMonth() property or not:

javascript— editable

But if you want to validate whether a value represents a valid date, use the following:

javascript— editable

This code attempts to convert the value to a Date object. If the conversion results in a valid date, it returns true; otherwise, it returns false.

The `toString()` Method

All objects have a <kbd class="highlighted">toString()</kbd> method called when an object should be represented as a text value, or an object is referred to in a manner in which a string is expected. Every object inherits the method from Object. If it is not overridden in a custom object, the <kbd class="highlighted">toString()</kbd> method returns "[object type]", where type is the type of the object. This behavior is exactly what the first method leverages for type checking.

Here is a practical example:

console.log(Object.prototype.toString.call(new Date())); // "[object Date]"
console.log(Object.prototype.toString.call("April 14, 2020")); // "[object String]"
console.log(Object.prototype.toString.call({})); // "[object Object]"