feat: Implement support for watch mode (#32)

Fixes #28. This patch adds a dependency on `yargs` to be able to parse
command-line arguments. If `--watch` is provided, it will be passed
along to the spawned Node.js child process. As a side effect of using
yargs, we now also support the commands `ts-node-test --version` and
`ts-node-test --help`.

.github/workflows/main.yml

@@ -27,6 +27,7 @@ jobs:
           - windows-latest
         node-version:
           - 18
+          - 19
     name: test (${{ matrix.os }}) - Node.js ${{ matrix.node-version }}
     runs-on: ${{ matrix.os }}
     steps:

README.md

@@ -7,7 +7,7 @@ You need to have `typescript` installed as a (dev) dependency and must be using
 
 Imagine it like `ts-node --test`, if that command existed.
 
-### How to use
+## Usage
 
 Install as a dev dependency:
 
@@ -29,17 +29,28 @@ The command syntax is similar to `node --test`. Multiple paths can be passed. Di
 for any files with supported extensions (currently: `.js`, `.mjs`, `.cjs`; `.ts`, `.mts`, `.cts`).
 Then, Node's test runner will be started on all files that were found in this process.
 
-You can also override the list of extensions by setting an environment variable (`TEST_EXTENSIONS`).
-Then, the default list of extensions will not be used during discovery and instead only listed extensions will be included.
-For example:
+### Extensions
+
+You can override the list of extensions by setting an environment variable (`TEST_EXTENSIONS`). This list will then be
+used instead of the default extensions. For example:
 
 ```
 TEST_EXTENSIONS=.test.ts,.test.js ts-node-test test/
 ```
 
 The above will recursively look for files in the `test/` directory ending in `.test.ts` or `.test.js`.
 
-### Why this is needed
+### Watch mode
+
+On Node.js versions that support watch mode in conjunction with the test runner, you can use it by passing the `--watch`
+argument. At time of writing, this is only possible on Node.js 19, but will likely be backported to Node.js 18 in the
+future.
+
+```
+ts-node-test --watch test/
+```
+
+## Why this is needed
 
 TL;DR: Node.js (at the time of writing) does not allow to override the list of extensions that are used when searching
 for test files. The official recommendation is to list all files explicitly. That is precisely what this CLI wrapper

package.json

@@ -43,13 +43,15 @@
     "@meyfa/eslint-config": "2.1.2",
     "@types/node": "18.11.17",
     "@types/sinon": "10.0.13",
+    "@types/yargs": "17.0.17",
     "eslint": "8.30.0",
     "rimraf": "3.0.2",
     "sinon": "15.0.1",
     "typescript": "4.9.4"
   },
   "dependencies": {
-    "ts-node": "10.9.1"
+    "ts-node": "10.9.1",
+    "yargs": "17.6.2"
   },
   "peerDependencies": {
     "typescript": "^4.0.0"

src/bin.ts

@@ -1,5 +1,21 @@
 #!/usr/bin/env node
 
 import { main } from './index.js'
+import yargs from 'yargs'
 
-await main()
+const parsedArgs = yargs(process.argv.slice(2)).command('* <paths...>', 'Run tests', (yargs) => {
+  return yargs.options({
+    watch: {
+      type: 'boolean',
+      default: false,
+      description: 'Run in watch mode'
+    }
+  }).positional('paths', {
+    type: 'string',
+    array: true,
+    demandOption: true,
+    description: 'Paths to test files'
+  })
+}).parseSync()
+
+await main(parsedArgs.paths, parsedArgs)