Add scroll offset support

Author: SchoppAx

src/index.js

@@ -7,11 +7,12 @@ export default {
       inserted(el, binding) {
         const scrollAnimate = ScrollAnimate(Date.now())
         const previousClassName = el.className
+        const offset = parseInt(el.dataset.animateOnscrollOffset || 0);
         let lastScrollTop = window.pageYOffset
         window.addEventListener('scroll', function() {
           let scrollTop = window.pageYOffset || document.documentElement.scrollTop
           const isUpwards = scrollTop < lastScrollTop
-          scrollAnimate.run(el, binding, {isUpwards, previousClassName})
+          scrollAnimate.run(el, binding, {offset, isUpwards, previousClassName})
           lastScrollTop = scrollTop <= 0 ? 0 : scrollTop
         }, false)
       }

tests/utils.js

@@ -1,10 +1,11 @@
 const createFixture = (instance, {  previousClassName = '',
                                     animationClass,
-                                    repeat = false }) => {
+                                    repeat = false,
+                                    offset = 0 }) => {
 
-  const run = function(isInView, isUpwards = false) {
+  const run = function(isInView, isUpwards = false, offset = 0) {
     instance.isInView = () => isInView
-    instance.run(this.el, this.binding, {isUpwards, previousClassName})
+    instance.run(this.el, this.binding, {offset, isUpwards, previousClassName})
   }
 
   return {
@@ -19,10 +20,10 @@ const createFixture = (instance, {  previousClassName = '',
     getClassName: function() { return this.el.className.trim() },
     getClassNames: function() { return this.getClassName().split(' ') },
     scrollDown: function(isInView) {
-      run.call(this, isInView)
+      run.call(this, isInView, false, offset)
     },
     scrollUp: function(isInView) {
-      run.call(this, isInView, true)
+      run.call(this, isInView, true, offset)
     }
   }
 }