Allow Number type in updateIn function (#67)

lib/util/splitPath.js

@@ -3,5 +3,5 @@ import reject from 'lodash/reject';
 export default function splitPath(path) {
   return Array.isArray(path) ?
     path :
-    reject(path.split('.'), x => !x);
+    reject((path + '').split('.'), x => !x);
 }

test/util/splitPath-spec.js

@@ -0,0 +1,22 @@
+import { expect } from 'chai';
+import splitPath from '../../lib/util/splitPath';
+
+describe('splitPath', () => {
+  it('treats a number as a single step path', () => {
+    const path = 1;
+    const result = splitPath(path);
+    expect(result).to.deep.equal(['1']);
+  });
+
+  it('handles arrays', () => {
+    const path = ['foo', 'bar', 'x'];
+    const result = splitPath(path);
+    expect(result).to.equal(path);
+  });
+
+  it('handles strings separated by dots', () => {
+    const path = 'bar.0.y';
+    const result = splitPath(path);
+    expect(result).to.deep.equal(['bar', '0', 'y']);
+  });
+});