From 8e746386fe4777c9d932e870ea156bf10d446b3b Mon Sep 17 00:00:00 2001
From: Ryan Dahl <ry@tinyclouds.org>
Date: Tue, 29 May 2018 06:30:16 -0400
Subject: [PATCH] Crash nicely on no argument.

---
 main.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/main.go b/main.go
index ce96c1e7fb..7da8cfd077 100644
--- a/main.go
+++ b/main.go
@@ -4,6 +4,7 @@ package deno
 
 import (
 	"flag"
+	"fmt"
 	"github.com/ry/v8worker2"
 	"os"
 	"runtime/pprof"
@@ -69,6 +70,12 @@ var main_map string
 func Init() {
 	workerArgs = FlagsParse()
 
+	if len(workerArgs) == 0 {
+		fmt.Fprintf(os.Stderr, "Usage: %s file.ts\n", os.Args[0])
+		flag.PrintDefaults()
+		os.Exit(1)
+	}
+
 	// Maybe start Golang CPU profiler.
 	// Use --prof for profiling JS.
 	if *flagGoProf != "" {