fix(Hits): limit the hitComponent to be only a function (#1912)

Author: mikaa123

packages/react-instantsearch/src/components/Hits.js

@@ -18,11 +18,7 @@ class Hits extends Component {
 
 Hits.propTypes = {
   hits: PropTypes.array,
-
-  hitComponent: PropTypes.oneOfType([
-    PropTypes.string,
-    PropTypes.func,
-  ]).isRequired,
+  hitComponent: PropTypes.func.isRequired,
 };
 
 Hits.defaultProps = {

packages/react-instantsearch/src/components/Hits.test.js

@@ -1,14 +1,17 @@
 /* eslint-env jest, jasmine */
 
-import React from 'react';
+import React, {PropTypes} from 'react';
 import renderer from 'react-test-renderer';
 
 import Hits from './Hits';
 
 describe('Hits', () => {
   it('accepts a hitComponent prop', () => {
     const hits = [{objectID: 0}, {objectID: 1}, {objectID: 2}];
-    const Hit = 'Hit';
+    const Hit = ({hit}) => <div id={hit.objectID}/>;
+    Hit.propTypes = {
+      hit: PropTypes.object,
+    };
     const tree = renderer.create(
       <Hits
         hitComponent={Hit}

packages/react-instantsearch/src/components/__snapshots__/Hits.test.js.snap

@@ -1,23 +1,11 @@
 exports[`Hits accepts a hitComponent prop 1`] = `
 <div
   className="ais-Hits__root">
-  <Hit
-    hit={
-      Object {
-        "objectID": 0,
-      }
-    } />
-  <Hit
-    hit={
-      Object {
-        "objectID": 1,
-      }
-    } />
-  <Hit
-    hit={
-      Object {
-        "objectID": 2,
-      }
-    } />
+  <div
+    id={0} />
+  <div
+    id={1} />
+  <div
+    id={2} />
 </div>
 `;