fix(coordinates): never return negative scroll positions (#28)

stipsan · web-flow · commit 39c8888645e4 · 2018-07-18T23:02:34.000+02:00
diff --git a/src/index.ts b/src/index.ts
@@ -381,9 +381,10 @@ export default (target: Element, options: Options): CustomScrollAction[] => {
         )
       }
 
-      // Apply scroll position offsets
-      blockScroll += viewportY
-      inlineScroll += viewportX
+      // Apply scroll position offsets and ensure they are within bounds
+      // @TODO add more test cases to cover this 100%
+      blockScroll = Math.max(0, blockScroll + viewportY)
+      inlineScroll = Math.max(0, inlineScroll + viewportX)
     } else {
       // Handle each scrolling frame that might exist between the target and the viewport
 

Original file line number	Diff line number	Diff line change
`@@ -381,9 +381,10 @@ export default (target: Element, options: Options): CustomScrollAction[] => {`
`381`	`381`	`)`
`382`	`382`	`}`
`383`	`383`
`384`		`- // Apply scroll position offsets`
`385`		`- blockScroll += viewportY`
`386`		`- inlineScroll += viewportX`
	`384`	`+ // Apply scroll position offsets and ensure they are within bounds`
	`385`	`+ // @TODO add more test cases to cover this 100%`
	`386`	`+ blockScroll = Math.max(0, blockScroll + viewportY)`
	`387`	`+ inlineScroll = Math.max(0, inlineScroll + viewportX)`
`387`	`388`	`} else {`
`388`	`389`	`// Handle each scrolling frame that might exist between the target and the viewport`
`389`	`390`