diff --git a/packages/core/src/Modifiers.ts b/packages/core/src/Modifiers.ts
index b6d4df11a..2e21178a6 100644
--- a/packages/core/src/Modifiers.ts
+++ b/packages/core/src/Modifiers.ts
@@ -3,7 +3,7 @@ import { Constructor, isConstructor } from '../../utils/src/utils';
 import { EventMixin } from '../../utils/src/EventMixin';
 import { VersionableArray } from './Memory/VersionableArray';
 
-export class Modifiers extends EventMixin {
+export class Modifiers extends EventMixin implements Iterable<Modifier> {
     private _contents: Modifier[];
     constructor(...modifiers: Array<Modifier | Constructor<Modifier>>) {
         super();
@@ -247,6 +247,20 @@ export class Modifiers extends EventMixin {
     toggle(modifier: Modifier | Constructor<Modifier>): void {
         this.remove(modifier) || this.append(modifier);
     }
+    /**
+     * Check that all `otherModifiers` ar contained within this ones.
+     *
+     * @param otherModifiers
+     */
+    contains(otherModifiers: Modifiers): boolean {
+        for (const otherModifier of otherModifiers) {
+            const foundModifier = this.find(m => m.isSameAs(otherModifier));
+            if (!foundModifier && !otherModifier.isSameAs(undefined)) {
+                return false;
+            }
+        }
+        return true;
+    }
     /**
      * Return true if the modifiers in this array are the same as the modifiers
      * in the given array (as defined by the `isSameAs` methods of the
@@ -255,17 +269,7 @@ export class Modifiers extends EventMixin {
      * @param otherModifiers
      */
     areSameAs(otherModifiers: Modifiers): boolean {
-        const modifiersMap = new Map(
-            this._contents?.map(a => [a, otherModifiers.find(b => a.isSameAs(b))]) || [],
-        );
-        const aModifiers = Array.from(modifiersMap.keys());
-        const bModifiers = Array.from(modifiersMap.values());
-
-        const allAinB = aModifiers.every(a => a.isSameAs(modifiersMap.get(a)));
-        const allBinA = otherModifiers.every(
-            b => bModifiers.includes(b) || b.isSameAs(this.find(b)),
-        );
-        return allAinB && allBinA;
+        return this.contains(otherModifiers) && otherModifiers.contains(this);
     }
     /**
      * Remove all modifiers.
@@ -306,6 +310,20 @@ export class Modifiers extends EventMixin {
     map<T>(callbackfn: (value: Modifier, index: number, array: Modifier[]) => T): T[] {
         return this._contents?.map(callbackfn) || [];
     }
+    /**
+     * Iterate through all modifiers.
+     */
+    [Symbol.iterator](): Iterator<Modifier> {
+        let index = -1;
+        const data = this._contents || [];
+
+        return {
+            next: (): IteratorResult<Modifier> => ({
+                value: data[++index],
+                done: !(index in data),
+            }),
+        };
+    }
     /**
      * @override
      */
diff --git a/packages/core/test/Modifiers.test.ts b/packages/core/test/Modifiers.test.ts
index 55be65f24..3502c6899 100644
--- a/packages/core/test/Modifiers.test.ts
+++ b/packages/core/test/Modifiers.test.ts
@@ -18,6 +18,11 @@ class ExtendedModifier extends Modifier {
         return otherModifier instanceof ExtendedModifier && this.value === otherModifier.value;
     }
 }
+class SameUndefinedModifier extends Modifier {
+    isSameAs(otherModifier: Modifier): boolean {
+        return otherModifier instanceof Modifier || typeof otherModifier === 'undefined';
+    }
+}
 describe('core', () => {
     describe('Modifiers', () => {
         describe('constructor()', () => {
@@ -505,6 +510,56 @@ describe('core', () => {
                 expect(modifiersMap[1] instanceof ExtendedModifier).to.be.true;
             });
         });
+        describe('contains()', () => {
+            it('should contain itself favorably', () => {
+                const m1 = new Modifier();
+                const m2 = new Modifier();
+                const modifiers1 = new Modifiers(m1, m2);
+                expect(modifiers1.contains(modifiers1)).to.be.true;
+            });
+            it('should contain a modifier that has the same favorably', () => {
+                const m1 = new ExtendedModifier(1);
+                const m2 = new ExtendedModifier(2);
+                const modifiers1 = new Modifiers(m1, m2);
+                const m1bis = new ExtendedModifier(1);
+                const m2bis = new ExtendedModifier(2);
+                const modifiers2 = new Modifiers(m1bis);
+                const modifiers3 = new Modifiers(m2bis);
+                const modifiers4 = new Modifiers(m1bis, m2bis);
+                expect(modifiers1.contains(modifiers2)).to.be.true;
+                expect(modifiers1.contains(modifiers3)).to.be.true;
+                expect(modifiers1.contains(modifiers4)).to.be.true;
+            });
+            it('should contain a modifier that has the same favorably even if their order is different', () => {
+                const m1 = new ExtendedModifier(1);
+                const m2 = new ExtendedModifier(2);
+                const modifiers1 = new Modifiers(m1, m2);
+                const modifiers2 = new Modifiers(m2, m1);
+                expect(modifiers1.contains(modifiers2)).to.be.true;
+            });
+            it('should contain a modifier that has the same favorably even if their order and instances are different', () => {
+                const m1 = new ExtendedModifier(1);
+                const m2 = new ExtendedModifier(2);
+                const modifiers1 = new Modifiers(m1, m2);
+                const m1bis = new ExtendedModifier(1);
+                const m2bis = new ExtendedModifier(2);
+                const modifiers2 = new Modifiers(m2bis, m1bis);
+                expect(modifiers1.contains(modifiers2)).to.be.true;
+            });
+            it('should match with modifiers that are the same with undefined', () => {
+                const m1 = new SameUndefinedModifier();
+                const modifiers1 = new Modifiers();
+                const modifiers2 = new Modifiers(m1);
+                expect(modifiers1.contains(modifiers2)).to.be.true;
+            });
+            it('should not contain the other modifiers', () => {
+                const m1 = new ExtendedModifier(1);
+                const modifiers1 = new Modifiers(m1);
+                const m2 = new ExtendedModifier(0);
+                const modifiers2 = new Modifiers(m2);
+                expect(modifiers1.contains(modifiers2)).to.be.false;
+            });
+        });
         describe('areSameAs()', () => {
             it('should know that an instance of Modifiers is the same as itself', () => {
                 const m1 = new Modifier();