From df3c05b1801383b6633acf4aa941c1195ebcd88d Mon Sep 17 00:00:00 2001
From: stelcheck <mtrudel@wizcorp.jp>
Date: Sun, 10 Dec 2017 13:12:45 +0900
Subject: [PATCH] Support trace-warnings flag, TS_NODE_OPTIONS

This will remap all `TS_NODE_` environment to
`NODE_` environment variables for the child process
being spawned.

Fixes #465 #471
---
 README.md  |  5 +++++
 src/bin.ts | 19 +++++++++++++++++--
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index b11a961e0..d35d1ac32 100644
--- a/README.md
+++ b/README.md
@@ -42,6 +42,11 @@ ts-node -p '"Hello, world!"'
 
 # Pipe scripts to execute with TypeScript.
 echo "console.log('Hello, world!')" | ts-node
+
+# Passing NODE_OPTIONS to the underlying process using TS_NODE_OPTIONS.
+# All `TS_NODE_*` environment variables will be passed as `NODE_*` environment
+# variables to your code.
+TS_NODE_ENV="--inspect-brk" ts-node
 ```
 
 ![TypeScript REPL](https://github.com/TypeStrong/ts-node/raw/master/screenshot.png)
diff --git a/src/bin.ts b/src/bin.ts
index 8b8e76401..0b2a69bbf 100644
--- a/src/bin.ts
+++ b/src/bin.ts
@@ -32,9 +32,21 @@ v8flags(function (err, v8flags) {
     '--perf-basic-prof',
     '--preserve-symlinks',
     '--expose-gc',
-    '--expose-http2'
+    '--expose-http2',
+    '--trace-warnings'
   ])
 
+  const env: { [key: string]: string | undefined } = {}
+
+  for (const key of Object.keys(process.env)) {
+    const val = process.env[key]
+    if (key.substring(0, 8) === 'TS_NODE_') {
+      env[key.substring(3)] = val
+    } else {
+      env[key] = val
+    }
+  }
+
   for (let i = 0; i < argv.length; i++) {
     const arg = argv[i]
     const flag = arg.split('=', 1)[0]
@@ -53,7 +65,10 @@ v8flags(function (err, v8flags) {
   const proc = spawn(
     process.execPath,
     nodeArgs.concat(join(__dirname, '_bin.js'), scriptArgs),
-    { stdio: 'inherit' }
+    {
+      env,
+      stdio: 'inherit'
+    }
   )
 
   proc.on('exit', function (code: number, signal: string) {