From 34bd65412a7700ffc2a46bf833b11891b9593c4c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hu=C3=A1ng=20J=C3=B9nli=C3=A0ng?= <i@jhuang.me>
Date: Thu, 29 Aug 2019 11:54:42 -0400
Subject: [PATCH] perf: lookahead only when functionSent is enabled

---
 packages/babel-parser/src/parser/statement.js | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/packages/babel-parser/src/parser/statement.js b/packages/babel-parser/src/parser/statement.js
index a761e6dfc77b..e993421bd481 100644
--- a/packages/babel-parser/src/parser/statement.js
+++ b/packages/babel-parser/src/parser/statement.js
@@ -167,7 +167,12 @@ export default class StatementParser extends ExpressionParser {
       case tt._for:
         return this.parseForStatement(node);
       case tt._function:
-        if (this.lookaheadCharCode() === charCodes.dot) break;
+        if (
+          this.hasPlugin("functionSent") &&
+          this.lookaheadCharCode() === charCodes.dot
+        ) {
+          break;
+        }
         if (context) {
           if (this.state.strict) {
             this.raise(