- a = reverse(a);
- b = reverse(b);
- var edits = diff(a, b);
- var partial = edits.slice(0, Math.round(p * edits.length));
- return reverse(patch(partial, a));
+
+ // The edit path works from the string end, forwards, because
+ // that's how Levenshtein edits work. To match LTR reading
+ // direction (and the behavior of fastLerp), swap the strings
+ // and invert the parameter when editing.
+ var edits = diff(b, a);
+ var partial = edits.slice(0, Math.round((1 - p) * edits.length));
+ return patch(partial, b);