fix: Allow default initialization of DateTime/Duration/Interval

src/datetime.js

@@ -513,7 +513,7 @@ export default class DateTime {
   /**
    * @access private
    */
-  constructor(config) {
+  constructor(config = {}) {
     const zone = config.zone || Settings.defaultZone;
 
     let invalid =

src/duration.js

@@ -217,7 +217,7 @@ export default class Duration {
   /**
    * @private
    */
-  constructor(config) {
+  constructor(config = {}) {
     const accurate = config.conversionAccuracy === "longterm" || false;
     let matrix = accurate ? accurateMatrix : casualMatrix;
 

src/interval.js

@@ -40,7 +40,7 @@ export default class Interval {
   /**
    * @private
    */
-  constructor(config) {
+  constructor(config = {}) {
     /**
      * @access private
      */

test/datetime/create.test.js

@@ -9,6 +9,13 @@ const withDefaultLocale = Helpers.withDefaultLocale,
   withthrowOnInvalid = Helpers.setUnset("throwOnInvalid"),
   withDefaultZone = Helpers.withDefaultZone;
 
+//------
+// new
+//------
+test("Default constructor works", () => {
+  expect(() => new DateTime()).not.toThrow();
+});
+
 //------
 // .now()
 //------

test/duration/create.test.js

@@ -2,6 +2,13 @@
 
 import { Duration } from "../../src/luxon";
 
+//------
+// new
+//------
+test("Default constructor works", () => {
+  expect(() => new Duration()).not.toThrow();
+});
+
 //------
 // .fromObject()
 //-------

test/interval/create.test.js

@@ -4,6 +4,13 @@ import Helpers from "../helpers";
 
 const withThrowOnInvalid = Helpers.setUnset("throwOnInvalid");
 
+//------
+// new
+//------
+test("Default constructor works", () => {
+  expect(() => new Interval()).not.toThrow();
+});
+
 //------
 // .fromObject()
 //-------