move unset into its own module, include tests

also fixes issue with recursive removal of properties

src/server/config/__tests__/unset.js

@@ -0,0 +1,83 @@
+import unset from '../unset';
+import expect from 'expect.js';
+
+describe('unset(obj, key)', function () {
+  describe('invalid input', function () {
+    it('should do nothing if not given an object', function () {
+      const obj = 'hello';
+      unset(obj, 'e');
+      expect(obj).to.equal('hello');
+    });
+
+    it('should do nothing if not given a key', function () {
+      const obj = { one: 1 };
+      unset(obj);
+      expect(obj).to.eql({ one: 1 });
+    });
+
+    it('should do nothing if given an empty string as a key', function () {
+      const obj = { one: 1 };
+      unset(obj, '');
+      expect(obj).to.eql({ one: 1 });
+    });
+  });
+
+  describe('shallow removal', function () {
+    let obj;
+
+    beforeEach(function () {
+      obj = { one: 1, two: 2, deep: { three: 3, four: 4 } };
+    });
+
+    it('should remove the param using a string key', function () {
+      unset(obj, 'two');
+      expect(obj).to.eql({ one: 1, deep: { three: 3, four: 4 } });
+    });
+
+    it('should remove the param using an array key', function () {
+      unset(obj, ['two']);
+      expect(obj).to.eql({ one: 1, deep: { three: 3, four: 4 } });
+    });
+  });
+
+  describe('deep removal', function () {
+    let obj;
+
+    beforeEach(function () {
+      obj = { one: 1, two: 2, deep: { three: 3, four: 4 } };
+    });
+
+    it('should remove the param using a string key', function () {
+      unset(obj, 'deep.three');
+      expect(obj).to.eql({ one: 1, two: 2, deep: { four: 4 } });
+    });
+
+    it('should remove the param using an array key', function () {
+      unset(obj, ['deep', 'three']);
+      expect(obj).to.eql({ one: 1, two: 2, deep: { four: 4 } });
+    });
+  });
+
+  describe('recursive removal', function () {
+    it('should clear object if only value is removed', function () {
+      const obj = { one: { two: { three: 3 } } };
+      unset(obj, 'one.two.three');
+      expect(obj).to.eql({});
+    });
+
+    it('should clear object if no props are left', function () {
+      const obj = { one: { two: { three: 3 } } };
+      unset(obj, 'one.two');
+      expect(obj).to.eql({});
+    });
+
+    it('should remove deep property, then clear the object', function () {
+      const obj = { one: { two: { three: 3, four: 4 } } };
+      unset(obj, 'one.two.three');
+      expect(obj).to.eql({ one: { two: { four: 4 } } });
+
+      unset(obj, 'one.two.four');
+      expect(obj).to.eql({});
+    });
+  });
+});

src/server/config/unset.js

@@ -0,0 +1,26 @@
+import _ from 'lodash';
+import toPath from 'lodash/internal/toPath';
+
+module.exports = function unset(object, rawPath) {
+  if (!object) return;
+  const path = toPath(rawPath);
+
+  switch (path.length) {
+    case 0:
+      return;
+
+    case 1:
+      delete object[rawPath];
+      break;
+
+    default:
+      const leaf = path.pop();
+      const parentPath = path.slice();
+      const parent = _.get(object, parentPath);
+      unset(parent, leaf);
+      if (!_.size(parent)) {
+        unset(object, parentPath);
+      }
+      break;
+  }
+};