@kpdecker your library is great so far. I think I might have found an edge case unless i'm missing something?

oldString = 'test\ntest2\n \ntest3\n';
"test
test2
 
test3
"

newString = 'test\ntest2\ntest3\n';
"test
test2
test3
"

Now I create a patch

d = JsDiff.createPatch('file/path.js', oldString, newString, '', '', { context: 0 });

This patch/diff looks correct

"Index: file/path.js
===================================================================
--- file/path.js	
+++ file/path.js	
@@ -3,1 +3,0 @@
- 

However when I apply the patch....

result = JsDiff.applyPatch(oldString, d);
"test
test2
 
"

We can see it seems to be affecting the wrong line number. Is it trimming somewhere on the oldString where it shouldn't be?