omit "()" after new when minifying

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+* Remove trailing `()` from `new` when minifying
+
+    Now `new Foo()` will be printed as `new Foo` when minifying (as long as it's safe to do so), resulting in slightly shorter minified code.
+
 ## 0.6.31
 
 * Invalid source maps are no longer an error ([#367](https://github.com/evanw/esbuild/issues/367))

internal/printer/printer.go

@@ -1292,16 +1292,18 @@ func (p *printer) printExpr(expr ast.Expr, level ast.L, flags int) {
 		p.printSpace()
 		p.printExpr(e.Target, ast.LNew, forbidCall)
 
-		// TODO: Omit this while minifying
-		p.print("(")
-		for i, arg := range e.Args {
-			if i != 0 {
-				p.print(",")
-				p.printSpace()
+		// Omit the "()" when minifying, but only when safe to do so
+		if !p.options.RemoveWhitespace || len(e.Args) > 0 || level >= ast.LPostfix {
+			p.print("(")
+			for i, arg := range e.Args {
+				if i != 0 {
+					p.print(",")
+					p.printSpace()
+				}
+				p.printExpr(arg, ast.LComma, 0)
 			}
-			p.printExpr(arg, ast.LComma, 0)
+			p.print(")")
 		}
-		p.print(")")
 
 		if wrap {
 			p.print(")")

internal/printer/printer_test.go

@@ -202,6 +202,13 @@ func TestNew(t *testing.T) {
 	expectPrinted(t, "new (import('foo')).bar", "new (import(\"foo\")).bar();\n")
 	expectPrinted(t, "new (import('foo')[bar])", "new (import(\"foo\"))[bar]();\n")
 	expectPrinted(t, "new (import('foo'))[bar]", "new (import(\"foo\"))[bar]();\n")
+
+	expectPrintedMinify(t, "new x", "new x;")
+	expectPrintedMinify(t, "new x.y", "new x.y;")
+	expectPrintedMinify(t, "(new x).y", "new x().y;")
+	expectPrintedMinify(t, "new x().y", "new x().y;")
+	expectPrintedMinify(t, "new x() + y", "new x+y;")
+	expectPrintedMinify(t, "new x() ** 2", "new x**2;")
 }
 
 func TestCall(t *testing.T) {