feat(fabric.Collection): contains -> deep option

CHANGELOG.md

@@ -6,6 +6,7 @@
 - fix(fabric.Object): support `excludeFromExport` set on `clipPath` [#7148](https://github.com/fabricjs/fabric.js/pull/7148).
 - fix(fabric.Group): support `excludeFromExport` set on objects [#7148](https://github.com/fabricjs/fabric.js/pull/7148).
 - fix(fabric.StaticCanvas): support `excludeFromExport` set on `backgroundColor`, `overlayColor`, `clipPath` [#7148](https://github.com/fabricjs/fabric.js/pull/7148).
+- feat(fabric.Collection): the `contains` method now accepts a second boolean parameter `deep`, checking all descendants, `collection.contains(obj, true)` [#7139](https://github.com/fabricjs/fabric.js/pull/7139).
 
 ## [4.5.1]
 

src/mixins/collection.mixin.js

@@ -142,10 +142,19 @@ fabric.Collection = {
   /**
    * Returns true if collection contains an object
    * @param {Object} object Object to check against
+   * @param {Boolean} [deep=false] `true` to check all descendants, `false` to check only `_objects`
    * @return {Boolean} `true` if collection contains an object
    */
-  contains: function(object) {
-    return this._objects.indexOf(object) > -1;
+  contains: function (object, deep) {
+    if (this._objects.indexOf(object) > -1) {
+      return true;
+    }
+    else if (deep) {
+      return this._objects.some(function (obj) {
+        return typeof obj.contains === 'function' && obj.contains(object, true);
+      });
+    }
+    return false;
   },
 
   /**

test/unit/collection.js

@@ -1,6 +1,7 @@
 (function() {
 
   var collection = fabric.Collection;
+  var collection2 = fabric.util.object.clone(collection);
 
   QUnit.module('fabric.Collection', {
     beforeEach: function() {
@@ -9,6 +10,7 @@
       delete collection.renderOnAddRemove;
       delete collection._onObjectAdded;
       delete collection._onObjectRemoved;
+      collection2._objects = [];
     }
   });
 
@@ -173,7 +175,16 @@
     assert.equal(returned, false, 'collection is empty so does not contains obj');
     collection.add(obj);
     returned = collection.contains(obj);
-    assert.equal(returned, true, 'collection contais obj');
+    assert.equal(returned, true, 'collection contains obj');
+    var obj2 = { type: 'b' };
+    collection2.add(obj2);
+    collection.add(collection2);
+    returned = collection.contains(obj2);
+    assert.equal(returned, false, 'collection deeply contains obj, this check is shallow');
+    returned = collection.contains(obj2, false);
+    assert.equal(returned, false, 'collection deeply contains obj, this check is shallow');
+    returned = collection.contains(obj2, true);
+    assert.equal(returned, true, 'collection deeply contains obj');
   });
 
   QUnit.test('complexity', function(assert) {