fix(object): has should return early if nothing to split

The `hasProperty` function is useful when using the delmiter to test
deep existence of properties, e.g. `one.two.three`. In the case where
it's a root-level property, performance tests show that returning early
is a performance gain.

lib/object/has-property.js

@@ -21,6 +21,9 @@ module.exports = function hasProperty(obj, string = '', sep = '.') {
   }
 
   const parts = string.split(sep)
+
+  if (parts.length === 1) return Object.prototype.hasOwnProperty.call(obj, string)
+
   let ret = obj
   /* eslint-disable-next-line no-unused-vars */
   const last = parts.pop()

test/unit/object.js

@@ -44,6 +44,8 @@ test('object', async (t) => {
     t.throws(() => {
       object.has(input, 'l1.l1p2.l3p2', 2)
     }, /must be a string/ig)
+
+    t.equal(has({one: 1}, 'one'), true, 'returns early if there is no delimiter to split')
   }).catch(threw)
 
   t.test('object.get', async (t) => {