Collection is iterable.

packages/xo-collection/src/collection.js

@@ -240,4 +240,12 @@ export default class Collection extends EventEmitter {
   get all () {
     return this._items
   }
+
+  * [Symbol.iterator] () {
+    const {_items: items} = this
+
+    for (let key in items) {
+      yield items[key]
+    }
+  }
 }

packages/xo-collection/src/collection.spec.js

@@ -36,6 +36,13 @@ describe('Collection', function () {
     return waitTicks()
   })
 
+  it('is iterable', function () {
+    const iterator = this.col[Symbol.iterator]()
+
+    expect(iterator.next()).to.eql({done: false, value: 0})
+    expect(iterator.next()).to.eql({done: true, value: undefined})
+  })
+
   describe('#add()', function () {
     it('adds item to the collection', function () {
       const spy = sinon.spy()