feat: Support for low-level agent access

Author: Jan Krems

lib/internal/inspect-repl.js

@@ -730,6 +730,15 @@ function createRepl(inspector) {
   });
 
   function initializeContext(context) {
+    inspector.domainNames.forEach(domain => {
+      Object.defineProperty(context, domain, {
+        value: inspector[domain],
+        enumerable: true,
+        configurable: true,
+        writeable: false,
+      });
+    });
+
     copyOwnProperties(context, {
       get help() {
         print(HELP);

lib/node-inspect.js

@@ -66,6 +66,15 @@ function runScript(script, scriptArgs, inspectPort, childPrint) {
 
 function createAgentProxy(domain, client) {
   const agent = new EventEmitter();
+  agent.then = function retrieveDocs(...args) {
+    // TODO: potentially fetch the protocol and pretty-print it here.
+    const descriptor = {
+      [util.inspect.custom](depth, { stylize }) {
+        return stylize(`[Agent ${domain}]`, 'special');
+      },
+    };
+    return Promise.resolve(descriptor).then(...args);
+  };
 
   return new Proxy(agent, {
     get(target, name) {
@@ -95,7 +104,8 @@ class NodeInspector {
 
     this.client = new ProtocolClient(options.port, options.host);
 
-    ['Debugger', 'Runtime'].forEach(domain => {
+    this.domainNames = ['Debugger', 'Runtime'];
+    this.domainNames.forEach(domain => {
       this[domain] = createAgentProxy(domain, this.client);
     });
     this.handleDebugEvent = (fullName, params) => {

test/cli/low-level.test.js

@@ -0,0 +1,27 @@
+'use strict';
+const { test } = require('tap');
+
+const startCLI = require('./start-cli');
+
+test('Debugger agent direct access', (t) => {
+  const cli = startCLI(['examples/empty.js']);
+
+  function onFatal(error) {
+    cli.quit();
+    throw error;
+  }
+
+  return cli.waitFor(/break/)
+    .then(() => cli.waitForPrompt())
+    .then(() => cli.command('scripts'))
+    .then(() => {
+      const [, scriptId] = cli.output.match(/^\* (\d+): examples\/empty.js/);
+      return cli.command(`Debugger.getScriptSource({ scriptId: '${scriptId}' })`);
+    })
+    .then(() => {
+      t.match(cli.output,
+        'scriptSource: \'(function (exports, require, module, __filename, __dirname) { \\n});\'');
+    })
+    .then(() => cli.quit())
+    .then(null, onFatal);
+});