Avoid unnecessary +0 in transform-es2015-parameters (babel#4738)

chrisprice · Oct 18, 2016 · 3142039 · 3142039
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commit 3142039
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diff --git a/packages/babel-plugin-transform-es2015-parameters/src/rest.js b/packages/babel-plugin-transform-es2015-parameters/src/rest.js
@@ -161,6 +161,9 @@ function optimiseIndexGetter(path, argsId, offset) {
 
   if (t.isNumericLiteral(path.parent.property)) {
     index = t.numericLiteral(path.parent.property.value + offset);
+  } else if (offset === 0) {
+    // Avoid unnecessary '+ 0'
+    index = path.parent.property;
   } else {
     index = t.binaryExpression("+", path.parent.property, t.numericLiteral(offset));
   }

diff --git a/...l-plugin-transform-es2015-parameters/test/fixtures/parameters/regression-4348/expected.js b/...l-plugin-transform-es2015-parameters/test/fixtures/parameters/regression-4348/expected.js
@@ -2,5 +2,5 @@ function first() {
   var _ref;
 
   var index = 0;
-  return _ref = index++ + 0, arguments.length <= _ref ? undefined : arguments[_ref];
+  return _ref = index++, arguments.length <= _ref ? undefined : arguments[_ref];
 }