How to check if obj is of type luxon?

Question

I am writing a date adapter for Angular Material, and need a function that returns a boolean if the provided object is a luxon DateTime.

Something like this (from moment):

isDateInstance(obj: any): boolean {
    return moment.isMoment(obj);
  }

What I have is this so far - is this good enough?:

isDateInstance(obj: any): boolean {
      try {
          const luxonObject = DateTime.fromObject(obj);
          return luxonObject.isValid;
      } catch (error) {
          return false;
      }
  }

Stowaway

Answer 1

I think that your code is fine, I would suggest that you can use native instanceof.

const DateTime = luxon.DateTime;

function isDateInstance(obj) {
    return obj instanceof DateTime;
}

console.log( isDateInstance('') );
console.log( isDateInstance({}) );
console.log( isDateInstance(new Date()) );
console.log( isDateInstance(DateTime.local()) );

<script src="https://moment.github.io/luxon/global/luxon.min.js"></script>

EDIT:

Luxon has added isDateTime method in v.1.6.0 that

Check if an object is a DateTime. Works across context boundaries

so an updated solution can be the following:

const DateTime = luxon.DateTime;

function isDateInstance(obj) {
    return DateTime.isDateTime(obj);
}

console.log( isDateInstance('') );
console.log( isDateInstance({}) );
console.log( isDateInstance(new Date()) );
console.log( isDateInstance(DateTime.local()) );

<script src="https://cdn.jsdelivr.net/npm/[email protected]/build/global/luxon.js"></script>

From v.1.6.0 until v.1.8.3 isDateTime will give undefined instead of false due to an issue.

Bollay