fs: re-export constants from fs/promises

Author: F3n67u

lib/fs/promises.js

@@ -1,3 +1,5 @@
 'use strict';
 
-module.exports = require('internal/fs/promises').exports;
+const fsPromises = require('internal/fs/promises').exports;
+fsPromises.constants = require('fs').constants;
+module.exports = fsPromises;

test/parallel/test-fs-promises-exists.js

@@ -2,5 +2,8 @@
 
 require('../common');
 const assert = require('assert');
+const fs = require('fs');
+const fsPromises = require('fs/promises');
 
-assert.strictEqual(require('fs/promises'), require('fs').promises);
+assert.strictEqual(fsPromises, fs.promises);
+assert.strictEqual(fsPromises.constants, fs.constants);