From 19f04253a70da832a719834909fd0213a9eb806d Mon Sep 17 00:00:00 2001
From: Thomas Goyne <tg@realm.io>
Date: Mon, 18 Jun 2018 10:03:17 -0700
Subject: [PATCH] shouldCompactOnLaunch is passed the used bytes, not unused
 bytes

---
 CHANGELOG.md     | 2 +-
 docs/realm.js    | 2 +-
 src/js_realm.hpp | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a9c3579b..2a0896c8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,7 +14,7 @@ X.Y.Z Release notes
   `shouldCompactOnLaunch` config property for them.
 
 ### Bug fixes
-* None.
+* Fix incorrect documentation of the `shouldCompactOnLaunch` parameters.
 
 ### Internals
 * None.
diff --git a/docs/realm.js b/docs/realm.js
index e6eb215d..0f376ffa 100644
--- a/docs/realm.js
+++ b/docs/realm.js
@@ -324,7 +324,7 @@ class Realm {
  *   a Realm for the first time during the life of a process to determine if it should be compacted
  *   before being returned to the user. The function takes two arguments:
  *     - `totalSize` - The total file size (data + free space)
- *     - `unusedSize` - The total bytes used by data in the file.
+ *     - `usedSize` - The total bytes used by data in the file.
  *   It returns `true` to indicate that an attempt to compact the file should be made. The compaction
  *   will be skipped if another process is accessing it.
  * @property {string} [path={@link Realm.defaultPath}] - The path to the file where the
diff --git a/src/js_realm.hpp b/src/js_realm.hpp
index fea2206f..2a11d51d 100644
--- a/src/js_realm.hpp
+++ b/src/js_realm.hpp
@@ -518,10 +518,10 @@ void RealmClass<T>::constructor(ContextType ctx, ObjectType this_object, size_t
                 }
 
                 FunctionType should_compact_on_launch_function = Value::validated_to_function(ctx, compact_value, "shouldCompactOnLaunch");
-                config.should_compact_on_launch_function = [=](uint64_t total_bytes, uint64_t unused_bytes) {
+                config.should_compact_on_launch_function = [=](uint64_t total_bytes, uint64_t used_bytes) {
                     ValueType arguments[2] = {
                         Value::from_number(ctx, total_bytes),
-                        Value::from_number(ctx, unused_bytes)
+                        Value::from_number(ctx, used_bytes)
                     };
 
                     ValueType should_compact = Function<T>::callback(ctx, should_compact_on_launch_function, this_object, 2, arguments);