chore(cli-repl): add run-Node.js-script execution mode

Author: addaleax

packages/cli-repl/src/run.spec.ts

@@ -0,0 +1,36 @@
+import childProcess from 'child_process';
+import path from 'path';
+import { promisify } from 'util';
+import { expect } from 'chai';
+const execFile = promisify(childProcess.execFile);
+
+describe('CLI entry point', () => {
+  async function run(args: string[], env?: Record<string, string>): Promise<{ stdout: string, stderr: string }> {
+    // Use ts-node to run the .ts files directly so nyc can pick them up for
+    // coverage.
+    return await execFile(
+      process.execPath,
+      ['-r', 'ts-node/register', path.resolve(__dirname, 'run.ts'), ...args],
+      { env: { ...process.env, ...(env ?? {}) } });
+  }
+
+  it('prints the version if --version is being used', async() => {
+    const { stdout } = await run(['--version']);
+    expect(stdout).to.match(/^\d+\.\d+\.\d+/);
+  });
+
+  it('prints the help text if --help is being used', async() => {
+    const { stdout } = await run(['--help']);
+    expect(stdout).to.include('$ mongosh [options]');
+  });
+
+  it('runs regular mongosh code otherwise', async() => {
+    const { stdout } = await run(['--nodb', '--norc', '--eval', '55 + 89']);
+    expect(stdout).to.include('144');
+  });
+
+  it('runs Node.js scripts if MONGOSH_RUN_NODE_SCRIPT is passed', async() => {
+    const { stdout } = await run([path.resolve(__dirname, '..', 'test', 'fixtures', 'nodescript.js')], { MONGOSH_RUN_NODE_SCRIPT: '1' });
+    expect(stdout).to.include('works!');
+  });
+});

packages/cli-repl/src/run.ts

@@ -1,8 +1,18 @@
 import { CliRepl, parseCliArgs, mapCliToDriver, getStoragePaths, getMongocryptdPaths, runSmokeTests, USAGE } from './index';
 import { generateUri } from '@mongosh/service-provider-server';
 import { redactCredentials } from '@mongosh/history';
+import { runMain } from 'module';
 
 (async() => {
+  if (process.env.MONGOSH_RUN_NODE_SCRIPT) {
+    if (process.execPath !== process.argv[1]) {
+      // node /path/to/this/file script ... -> node script ...
+      process.argv.splice(1, 1);
+    }
+    (runMain as any)(process.argv[1]);
+    return;
+  }
+
   let repl;
   try {
     const options = parseCliArgs(process.argv);

packages/cli-repl/test/fixtures/nodescript.js

@@ -0,0 +1,3 @@
+const assert = require('assert');
+assert.strictEqual(typeof print, 'undefined');
+console.log('works!');