From 1c4d509a404c3b383f9f1fc016fd0408be3eab53 Mon Sep 17 00:00:00 2001
From: "Fred K. Schott" <fkschott@gmail.com>
Date: Fri, 30 Oct 2020 08:31:04 -0700
Subject: [PATCH] add args support for typescript plugin

---
 plugins/plugin-typescript/README.md           | 6 ++++++
 plugins/plugin-typescript/plugin.js           | 4 ++--
 plugins/plugin-typescript/test/plugin.test.js | 5 +++++
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/plugins/plugin-typescript/README.md b/plugins/plugin-typescript/README.md
index a16cfbe41f..c0935b2303 100644
--- a/plugins/plugin-typescript/README.md
+++ b/plugins/plugin-typescript/README.md
@@ -19,3 +19,9 @@ module.exports = {
   plugins: ['@snowpack/plugin-typescript'],
 };
 ```
+
+## Plugin Options
+
+| Name   |   Type   | Description                                                                                                                                                                      |
+| :----- | :------: | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `args` | `string` | Optional arguments to pass to the `tsc` CLI. For example, you can configure a custom project directory (with a custom `tsconfig.json` file) using `args: "--project ./your/custom/path"`. |
diff --git a/plugins/plugin-typescript/plugin.js b/plugins/plugin-typescript/plugin.js
index 151881dc58..a295cb260a 100644
--- a/plugins/plugin-typescript/plugin.js
+++ b/plugins/plugin-typescript/plugin.js
@@ -2,11 +2,11 @@ const execa = require('execa');
 const npmRunPath = require('npm-run-path');
 const cwd = process.cwd();
 
-function typescriptPlugin() {
+function typescriptPlugin(_, {args} = {}) {
   return {
     name: '@snowpack/plugin-typescript',
     async run({isDev, log}) {
-      const workerPromise = execa.command(`tsc --noEmit ${isDev ? '--watch' : ''}`, {
+      const workerPromise = execa.command(`tsc --noEmit ${isDev ? '--watch' : ''} ${args ? args : ''}`, {
         env: npmRunPath.env(),
         extendEnv: true,
         windowsHide: false,
diff --git a/plugins/plugin-typescript/test/plugin.test.js b/plugins/plugin-typescript/test/plugin.test.js
index 13cf03b151..06207a2f22 100644
--- a/plugins/plugin-typescript/test/plugin.test.js
+++ b/plugins/plugin-typescript/test/plugin.test.js
@@ -31,6 +31,11 @@ describe('plugin-typescript', () => {
     expect(execaFn.mock.calls[0][0]).toContain('--noEmit');
     expect(execaFn.mock.calls[0][0]).toContain('--watch');
   });
+  test('calls "tsc" correctly with args', async () => {
+    const p = plugin(undefined, {args: '--foo bar'});
+    await p.run({isDev: false, log: jest.fn});
+    expect(execaFn.mock.calls[0][0]).toContain('--foo bar');
+  });
   test('handles tsc output', async () => {
     const logFn = jest.fn();
     const p = plugin();