feat: add rescale option to Duration.normalize method (#1299)

src/duration.js

@@ -155,6 +155,17 @@ function normalizeValues(matrix, vals) {
   }, null);
 }
 
+// Remove all properties with a value of 0 from an object
+function removeZeroes(vals) {
+  const newVals = {};
+  for (const [key, value] of Object.entries(vals)) {
+    if (value !== 0) {
+      newVals[key] = value;
+    }
+  }
+  return newVals;
+}
+
 /**
  * A Duration object represents a period of time, like "2 months" or "1 day, 1 hour". Conceptually, it's just a map of units to their quantities, accompanied by some additional configuration and methods for creating, parsing, interrogating, transforming, and formatting them. They can be used on their own or in conjunction with other Luxon types; for example, you can use {@link DateTime#plus} to add a Duration object to a DateTime, producing another DateTime.
  *
@@ -701,6 +712,17 @@ export default class Duration {
     return clone(this, { values: vals }, true);
   }
 
+  /**
+   * Rescale units to its largest representation
+   * @example Duration.fromObject({ milliseconds: 90000 }).rescale().toObject() //=> { minutes: 1, seconds: 30 }
+   * @return {Duration}
+   */
+  rescale() {
+    if (!this.isValid) return this;
+    const vals = removeZeroes(this.normalize().shiftToAll().toObject());
+    return clone(this, { values: vals }, true);
+  }
+
   /**
    * Convert this Duration into its representation in a different set of units.
    * @example Duration.fromObject({ hours: 1, seconds: 30 }).shiftTo('minutes', 'milliseconds').toObject() //=> { minutes: 60, milliseconds: 30000 }
@@ -765,6 +787,25 @@ export default class Duration {
     return clone(this, { values: built }, true).normalize();
   }
 
+  /**
+   * Shift this Duration to all available units.
+   * Same as shiftTo("years", "months", "weeks", "days", "hours", "minutes", "seconds", "milliseconds")
+   * @return {Duration}
+   */
+  shiftToAll() {
+    if (!this.isValid) return this;
+    return this.shiftTo(
+      "years",
+      "months",
+      "weeks",
+      "days",
+      "hours",
+      "minutes",
+      "seconds",
+      "milliseconds"
+    );
+  }
+
   /**
    * Return the negative of this Duration.
    * @example Duration.fromObject({ hours: 1, seconds: 30 }).negate().toObject() //=> { hours: -1, seconds: -30 }

test/duration/units.test.js

@@ -96,6 +96,29 @@ test("Duration#shiftTo boils hours down to hours and minutes", () => {
   });
 });
 
+//------
+// #shiftToAll()
+//-------
+test("Duration#shiftToAll shifts to all available units", () => {
+  const dur = Duration.fromMillis(5760000).shiftToAll();
+  expect(dur.toObject()).toEqual({
+    years: 0,
+    months: 0,
+    weeks: 0,
+    days: 0,
+    hours: 1,
+    minutes: 36,
+    seconds: 0,
+    milliseconds: 0,
+  });
+});
+
+test("Duration#shiftToAll maintains invalidity", () => {
+  const dur = Duration.invalid("because").shiftToAll();
+  expect(dur.isValid).toBe(false);
+  expect(dur.invalidReason).toBe("because");
+});
+
 //------
 // #normalize()
 //-------
@@ -207,6 +230,30 @@ test("Duration#normalize can convert all unit pairs", () => {
   }
 });
 
+//------
+// #rescale()
+//-------
+test("Duration#rescale normalizes, shifts to all units and remove units with a value of 0", () => {
+  const sets = [
+    [{ milliseconds: 90000 }, { minutes: 1, seconds: 30 }],
+    [
+      { minutes: 70, milliseconds: 12100 },
+      { hours: 1, minutes: 10, seconds: 12, milliseconds: 100 },
+    ],
+    [{ months: 2, days: -30 }, { months: 1 }],
+  ];
+
+  sets.forEach(([from, to]) => {
+    expect(Duration.fromObject(from).rescale().toObject()).toEqual(to);
+  });
+});
+
+test("Duration#rescale maintains invalidity", () => {
+  const dur = Duration.invalid("because").rescale();
+  expect(dur.isValid).toBe(false);
+  expect(dur.invalidReason).toBe("because");
+});
+
 //------
 // #as()
 //-------