Swap #valueOf and #toMillis

docs/moment.md

@@ -141,7 +141,7 @@ See the [formatting guide](formatting.html) for more about the string-outputting
 | RFC 2822             |                | `toRFC2822()`    |                                                                                                                                                   |
 | HTTP date string     |                | `toHTTP()`       |                                                                                                                                                   |
 | JS Date              | `toDate()`     | `toJSDate()`     |                                                                                                                                                   |
-| Epoch time           | `valueOf()`    | `valueOf()` or `toMillis()`      |                                                                                                                                                   |
+| Epoch time           | `valueOf()`    | `toMillis()` or `valueOf()`      |                                                                                                                                                   |
 | Object               | `toObject()`   | `toObject()`     |                                                                                                                                                   |
 | Duration             | `diff(Moment)` | `diff(DateTime)` | Moment's diff returns a count of milliseconds, but Luxon's returns a Duration. To replicate the Moment behavior, use `dt1.diff(d2).milliseconds`. |
 

src/datetime.js

@@ -340,7 +340,7 @@ function quickDT(obj, zone) {
  * * **Week calendar**: For ISO week calendar attributes, see the {@link weekYear}, {@link weekNumber}, and {@link weekday} accessors.
  * * **Configuration** See the {@link locale} and {@link numberingSystem} accessors.
  * * **Transformation**: To transform the DateTime into other DateTimes, use {@link set}, {@link reconfigure}, {@link setZone}, {@link setLocale}, {@link plus}, {@link minus}, {@link endOf}, {@link startOf}, {@link toUTC}, and {@link toLocal}.
- * * **Output**: To convert the DateTime to other representations, use the {@link toJSON}, {@link toISO}, {@link toHTTP}, {@link toObject}, {@link toRFC2822}, {@link toString}, {@link toLocaleString}, {@link toFormat}, {@link valueOf} and {@link toJSDate}.
+ * * **Output**: To convert the DateTime to other representations, use the {@link toJSON}, {@link toISO}, {@link toHTTP}, {@link toObject}, {@link toRFC2822}, {@link toString}, {@link toLocaleString}, {@link toFormat}, {@link toMillis} and {@link toJSDate}.
  *
  * There's plenty others documented below. In addition, for more information on subtler topics like internationalization, time zones, alternative calendars, validity, and so on, see the external documentation.
  */
@@ -1506,19 +1506,19 @@ export default class DateTime {
   }
 
   /**
-   * Returns the epoch milliseconds of this DateTime
+   * Returns the epoch milliseconds of this DateTime. Alias of {@link toMillis}
    * @return {number}
    */
   valueOf() {
-    return this.isValid ? this.ts : NaN;
+    return this.toMillis();
   }
 
   /**
-   * Returns the epoch milliseconds of this DateTime. Alias of {@link valueOf}
+   * Returns the epoch milliseconds of this DateTime.
    * @return {number}
    */
   toMillis() {
-    return this.valueOf();
+    return this.isValid ? this.ts : NaN;
   }
 
   /**