feat(cli): add --help and --version options to main command (#35)

.changeset/wild-jeans-guess.md

@@ -0,0 +1,5 @@
+---
+'@emigrate/cli': minor
+---
+
+Add --help and --version options to main command

packages/cli/src/cli.ts

@@ -326,17 +326,28 @@ const commands: Record<string, Action> = {
   new: newMigration,
 };
 
-const command = process.argv[2]?.toLowerCase();
-const action = command ? commands[command] : undefined;
+const main: Action = async (args) => {
+  const { values, positionals } = parseArgs({
+    args,
+    options: {
+      help: {
+        type: 'boolean',
+        short: 'h',
+      },
+      version: {
+        type: 'boolean',
+        short: 'v',
+      },
+    },
+    allowPositionals: true,
+  });
 
-if (!action) {
-  if (command) {
-    console.error(`Unknown command: ${command}\n`);
-  } else {
-    console.error('No command specified\n');
-  }
+  const usage = `Usage: emigrate <options>/<command>
 
-  console.log(`Usage: emigrate <command>
+Options:
+
+  -h, --help     Show this help message and exit
+  -v, --version  Print version number and exit
 
 Commands:
 
@@ -344,12 +355,34 @@ Commands:
   new     Create a new migration file
   list    List all migrations and their status
   remove  Remove entries from the migration history
-`);
-  process.exit(1);
+`;
+
+  const command = positionals[0]?.toLowerCase();
+  const action = command ? commands[command] : undefined;
+
+  if (!action) {
+    if (command) {
+      console.error(`Unknown command: ${command}\n`);
+    } else if (values.version) {
+      const { getPackageInfo } = await import('./get-package-info.js');
+      const { version } = await getPackageInfo();
+      console.log(version);
+      process.exitCode = 0;
+      return;
+    } else if (!values.help) {
+      console.error('No command specified\n');
+    }
+
+    console.log(usage);
+    process.exitCode = 1;
+    return;
   }
 
-try {
   await action(process.argv.slice(3));
+};
+
+try {
+  await main(process.argv.slice(2));
 } catch (error) {
   if (error instanceof Error) {
     console.error(error.message);

packages/cli/src/get-package-info.ts

@@ -0,0 +1,28 @@
+import fs from 'node:fs/promises';
+import { fileURLToPath } from 'node:url';
+
+type PackageInfo = {
+  version: string;
+};
+
+export const getPackageInfo = async () => {
+  const packageInfoPath = fileURLToPath(new URL('../package.json', import.meta.url));
+
+  try {
+    const content = await fs.readFile(packageInfoPath, 'utf8');
+    const packageJson: unknown = JSON.parse(content);
+
+    if (
+      typeof packageJson === 'object' &&
+      packageJson &&
+      'version' in packageJson &&
+      typeof packageJson.version === 'string'
+    ) {
+      return packageJson as PackageInfo;
+    }
+  } catch {
+    // ignore
+  }
+
+  throw new Error(`Could not read package info from: ${packageInfoPath}`);
+};