fix: do not mutate objects when values do not change

Author: haggholm

lib/dereference.js

@@ -57,13 +57,19 @@ function crawl (obj, path, pathFromRoot, parents, $refs, options) {
  if ($Ref.isAllowed$Ref(value, options)) {
  dereferenced = dereference$Ref(value, keyPath, keyPathFromRoot, parents, $refs, options);
  circular = dereferenced.circular;
- obj[key] = dereferenced.value;
+ // Avoid pointless mutations; breaks frozen objects to no profit
+ if (obj[key] !== dereferenced.value) {
+ obj[key] = dereferenced.value;
+ }
  }
  else {
  if (parents.indexOf(value) === -1) {
  dereferenced = crawl(value, keyPath, keyPathFromRoot, parents, $refs, options);
  circular = dereferenced.circular;
- obj[key] = dereferenced.value;
+ // Avoid pointless mutations; breaks frozen objects to no profit
+ if (obj[key] !== dereferenced.value) {
+ obj[key] = dereferenced.value;
+ }
  }
  else {
  circular = foundCircularReference(keyPath, $refs, options);