Use slice for startsWith

Smaller, and faster https://jsbench.github.io/#eecce07acdcdd7a0287ca1369c4b87b4
lit · Mar 4, 2019 · 9a8ca40 · 9a8ca40
1 parent 12446c8
commit 9a8ca40
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Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/src/lib/modify-template.ts b/src/lib/modify-template.ts
@@ -69,5 +69,5 @@ const removePartForMarker =
 
 const isPartMarker = (comment: Node|null): comment is Comment => {
   return comment !== null && comment.nodeType === 8 /* Node.COMMENT_NODE */ &&
-      (comment as Comment).data.lastIndexOf(partMarker, 0) === 0;
+      (comment as Comment).data.slice(0, partMarker.length) === partMarker;
 };
diff --git a/src/lib/template-instance.ts b/src/lib/template-instance.ts
@@ -95,7 +95,7 @@ export class TemplateInstance {
       }
 
       // Does this comment start with the part marker?
-      if (data.lastIndexOf(partMarker, 0) === 0) {
+      if (data.slice(0, partMarker.length) === partMarker) {
         // The part marker packs the part index in the 16 low bits and
         // attribute count (if it's an attribute binding) in the 16 high bits.
         const packed = parseInt(data.slice(partMarker.length), 10);