[v6.x] module: add builtinModules

doc/api/modules.md

@@ -633,5 +633,29 @@ object.  Since `require()` returns the `module.exports`, and the `module` is
 typically *only* available within a specific module's code, it must be
 explicitly exported in order to be used.
 
+## The `Module` Object
+
+<!-- YAML
+added: v0.3.7
+-->
+
+* {Object}
+
+Provides general utility methods when interacting with instances of
+`Module` -- the `module` variable often seen in file modules. Accessed
+via `require('module')`.
+
+### module.builtinModules
+<!-- YAML
+added: REPLACEME
+-->
+
+* {string[]}
+
+A list of  the names of all modules provided by Node.js. Can be used to verify
+if a module is maintained by a third-party module or not.
+
+[`__dirname`]: #modules_dirname
+[`__filename`]: #modules_filename
 [`Error`]: errors.html#errors_class_error
 [module resolution]: #modules_all_together

lib/module.js

@@ -48,9 +48,16 @@ function Module(id, parent) {
 }
 module.exports = Module;
 
+const builtinModules = Object.keys(NativeModule._source)
+  .filter(NativeModule.nonInternalExists);
+
+Object.freeze(builtinModules);
+Module.builtinModules = builtinModules;
+
 Module._cache = {};
 Module._pathCache = {};
 Module._extensions = {};
+
 var modulePaths = [];
 Module.globalPaths = [];
 

test/parallel/test-module-builtin.js

@@ -0,0 +1,14 @@
+'use strict';
+require('../common');
+const assert = require('assert');
+const { builtinModules } = require('module');
+
+// Includes modules in lib/ (even deprecated ones)
+assert(builtinModules.includes('http'));
+assert(builtinModules.includes('sys'));
+
+// Does not include internal modules
+assert.deepStrictEqual(
+  builtinModules.filter((mod) => mod.startsWith('internal/')),
+  []
+);