feat(Sticky): add styleElement prop (#3202)

feat(Sticky): add `styleElement` prop

src/modules/Sticky/Sticky.d.ts

@@ -63,6 +63,9 @@ export interface StrictStickyProps {
 
   /** Context which sticky should attach onscroll events. */
   scrollContext?: object
+
+  /** Custom style for sticky element. */
+  styleElement?: object
 }
 
 declare const Sticky: React.ComponentClass<StickyProps>

src/modules/Sticky/Sticky.js

@@ -74,6 +74,9 @@ export default class Sticky extends Component {
 
     /** Context which sticky should attach onscroll events. */
     scrollContext: PropTypes.object,
+
+    /** Custom style for sticky element. */
+    styleElement: PropTypes.object,
   }
 
   static defaultProps = {
@@ -200,13 +203,15 @@ export default class Sticky extends Component {
   }
 
   computeStyle() {
+    const { styleElement } = this.props
     const { bottom, bound, sticky, top } = this.state
 
-    if (!sticky) return {}
+    if (!sticky) return styleElement
     return {
       bottom: bound ? 0 : bottom,
       top: bound ? undefined : top,
       width: this.triggerRect.width,
+      ...styleElement,
     }
   }
 

test/specs/modules/Sticky/Sticky-test.js

@@ -401,6 +401,15 @@ describe('Sticky', () => {
     })
   })
 
+  describe('styleElement', () => {
+    it('is passed to macthing element', () => {
+      wrapperMount(<Sticky styleElement={{ zIndex: 10 }} />)
+      const element = wrapper.childAt(0).childAt(1)
+
+      element.should.have.style('z-index', '10')
+    })
+  })
+
   describe('update', () => {
     it('is called on scroll', () => {
       const instance = mount(<Sticky />).instance()