1 files changed, 95 insertions, 0 deletions
diff --git a/node_modules/luxon/src/impl/diff.js b/node_modules/luxon/src/impl/diff.js
new file mode 100644
index 0000000..ebd129e
--- /dev/null
+++ b/node_modules/luxon/src/impl/diff.js
@@ -0,0 +1,95 @@
+import Duration from "../duration.js";
+
+function dayDiff(earlier, later) {
+  const utcDayStart = (dt) => dt.toUTC(0, { keepLocalTime: true }).startOf("day").valueOf(),
+    ms = utcDayStart(later) - utcDayStart(earlier);
+  return Math.floor(Duration.fromMillis(ms).as("days"));
+}
+
+function highOrderDiffs(cursor, later, units) {
+  const differs = [
+    ["years", (a, b) => b.year - a.year],
+    ["quarters", (a, b) => b.quarter - a.quarter + (b.year - a.year) * 4],
+    ["months", (a, b) => b.month - a.month + (b.year - a.year) * 12],
+    [
+      "weeks",
+      (a, b) => {
+        const days = dayDiff(a, b);
+        return (days - (days % 7)) / 7;
+      },
+    ],
+    ["days", dayDiff],
+  ];
+
+  const results = {};
+  const earlier = cursor;
+  let lowestOrder, highWater;
+
+  /* This loop tries to diff using larger units first.
+     If we overshoot, we backtrack and try the next smaller unit.
+     "cursor" starts out at the earlier timestamp and moves closer and closer to "later"
+     as we use smaller and smaller units.
+     highWater keeps track of where we would be if we added one more of the smallest unit,
+     this is used later to potentially convert any difference smaller than the smallest higher order unit
+     into a fraction of that smallest higher order unit
+  */
+  for (const [unit, differ] of differs) {
+    if (units.indexOf(unit) >= 0) {
+      lowestOrder = unit;
+
+      results[unit] = differ(cursor, later);
+      highWater = earlier.plus(results);
+
+      if (highWater > later) {
+        // we overshot the end point, backtrack cursor by 1
+        results[unit]--;
+        cursor = earlier.plus(results);
+
+        // if we are still overshooting now, we need to backtrack again
+        // this happens in certain situations when diffing times in different zones,
+        // because this calculation ignores time zones
+        if (cursor > later) {
+          // keep the "overshot by 1" around as highWater
+          highWater = cursor;
+          // backtrack cursor by 1
+          results[unit]--;
+          cursor = earlier.plus(results);
+        }
+      } else {
+        cursor = highWater;
+      }
+    }
+  }
+
+  return [cursor, results, highWater, lowestOrder];
+}
+
+export default function (earlier, later, units, opts) {
+  let [cursor, results, highWater, lowestOrder] = highOrderDiffs(earlier, later, units);
+
+  const remainingMillis = later - cursor;
+
+  const lowerOrderUnits = units.filter(
+    (u) => ["hours", "minutes", "seconds", "milliseconds"].indexOf(u) >= 0
+  );
+
+  if (lowerOrderUnits.length === 0) {
+    if (highWater < later) {
+      highWater = cursor.plus({ [lowestOrder]: 1 });
+    }
+
+    if (highWater !== cursor) {
+      results[lowestOrder] = (results[lowestOrder] || 0) + remainingMillis / (highWater - cursor);
+    }
+  }
+
+  const duration = Duration.fromObject(results, opts);
+
+  if (lowerOrderUnits.length > 0) {
+    return Duration.fromMillis(remainingMillis, opts)
+      .shiftTo(...lowerOrderUnits)
+      .plus(duration);
+  } else {
+    return duration;
+  }
+}