Checks if any value is of the type obtained from its object class equal to 'date' or an object type and an instance of Date. It confirms it's a valid date with the isNaN() function.

const isDate = <Payload extends object>(
  value: any,
  callback: ResultCallback<any, Payload> = resultCallback,
  payload?: Payload
): value is Date =>
    (typeOf(value) === 'date' || typeof value === 'object') &&
    value instanceof Date === true &&

Generic type variables


The Payload generic type variable constrained by object indicates the type of optional parameter payload of the supplied callback function and payload optional parameter of the isDate() function from which it captures its value.


value: any

The value of any type to check.

callback: ResultCallback<any, Payload>

A callback function of ResultCallback type with parameters, the value that has been checked, the result of this check, and payload of generic type variable Payload with optional properties from the provided payload, to handle them before the result return. By default, it uses resultCallback() function.

payload?: Payload

An optional object of the generic type variable Payload is assigned to the payload of the given callback function.

Return type

value is Date

The return type is a boolean as the result of its statement, indicating the value is a Date.


The return value is a boolean indicating whether the provided value is a Date.

Example usage

Basic example

// Example usage.
import { isDate } from '@angular-package/type';

const DATE = new Date(1995, 11, 17, 3, 24, 0);

isDate(new Date('December 17, 1995 03:24:00')), // true
isDate(new Date('1995-12-17T03:24:00')), // true
isDate(new Date(1995, 11, 17)), // true
isDate(new Date(628021800000)), // true
isDate(DATE); // Returns `true` as `value is Date`

Parameters callback and payload

// Callback and payload parameters example usage.
import { isDate } from '@angular-package/type';

isDate(DATE, (result, payload) => {
  if (payload) {
    result // Returns `true`
    payload.value // Returns new date
    payload.birthDay // Returns `14`
  return result;
}, { birthDay: 14 }); // Returns `true` as `value is Date`

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