New Collection#unset().

packages/xo-collection/README.md

@@ -82,6 +82,15 @@ col.remove('bar')
 
 - **Throws** `NoSuchItem` if the item is not in the collection.
 
+**Removing an item without error**
+
+This is the symmetric method of `set()`: it removes the item if it
+exists otherwise does nothing.
+
+```javascript
+col.unset('bar')
+```
+
 **Removing all items**
 
 ```javascript

packages/xo-collection/src/collection.js

@@ -144,6 +144,16 @@ export default class Collection extends EventEmitter {
     return this.get(key)
   }
 
+  unset (keyOrObjectWithId) {
+    const [key] = this._resolveItem(keyOrObjectWithId)
+
+    if (this.has(key)) {
+      delete this._items[key]
+      this._size--
+      this._touch('remove', key)
+    }
+  }
+
   update (keyOrObjectWithId, valueIfKey = undefined) {
     const [key, value] = this._resolveItem(keyOrObjectWithId, valueIfKey)
     this._assertHas(key)

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

@@ -204,6 +204,34 @@ describe('Collection', function () {
     })
   })
 
+  describe('#unset()', function () {
+    it('removes an existing item', function () {
+      this.col.unset('bar')
+
+      expect(this.col.has('bar')).to.be.false()
+
+      return eventToPromise(this.col, 'remove').then(function (removed) {
+        expect(removed).to.have.all.keys('bar')
+        expect(removed.bar).to.not.exist()
+      })
+    })
+
+    it('does not throw if the item does not exists', function () {
+      this.col.unset('foo')
+    })
+
+    it('accepts an object with an id property', function () {
+      this.col.unset({id: 'bar'})
+
+      expect(this.col.has('bar')).to.be.false()
+
+      return eventToPromise(this.col, 'remove').then(function (removed) {
+        expect(removed).to.have.all.keys('bar')
+        expect(removed.bar).to.not.exist()
+      })
+    })
+  })
+
   describe('touch()', function () {
     it('can be used to signal an indirect update', function () {
       const foo = { id: 'foo' }