[WIP] fs: feature detection for recursive mkdir[Sync]

doc/api/fs.md

@@ -2086,13 +2086,11 @@ fs.mkdir('/tmp/a/apple', { recursive: true }, (err) => {
 });
 ```
 
-`fs.mkdir` has non-enumerable non-writable property `Symbol('recursive')` that
-can be used to detect if the recursive feature is available
+The `util.features` symbol can be used to feature detect if
+recusion is available.
 
 ```js
-Object.getOwnPropertySymbols(fs.mkdir).map((sym) => {
-  return sym.toString();
-}).includes('Symbol(recursive)');
+fs.mkdir[util.features].includes('recursive');
 // true
 ```
 
@@ -2116,13 +2114,11 @@ changes:
 Synchronously creates a directory. Returns `undefined`.
 This is the synchronous version of [`fs.mkdir()`][].
 
-`fs.mkdirSync` has non-enumerable non-writable property `Symbol('recursive')`
-that can be used to detect if the recursive feature is available
+The `util.features` symbol can be used to feature detect if
+recusion is available.
 
 ```js
-Object.getOwnPropertySymbols(fs.mkdirSync).map((sym) => {
-  return sym.toString();
-}).includes('Symbol(recursive)');
+fs.mkdirSync[util.features].includes('recursive');
 // true
 ```
 

doc/api/util.md

@@ -179,6 +179,13 @@ The `--throw-deprecation` command line flag and `process.throwDeprecation`
 property take precedence over `--trace-deprecation` and
 `process.traceDeprecation`.
 
+### util.features
+<!-- YAML
+added: REPlACEME
+-->
+
+* {symbol} that can be used to do feature detection.
+
 ## util.format(format[, ...args])
 <!-- YAML
 added: v0.5.3

lib/fs.js

@@ -39,7 +39,7 @@ const {
   O_SYMLINK
 } = constants;
 
-const { _extend } = require('util');
+const { _extend, features } = require('util');
 const pathModule = require('path');
 const { isUint8Array } = require('internal/util/types');
 const binding = process.binding('fs');
@@ -745,12 +745,10 @@ function mkdir(path, options, callback) {
                 validateMode(mode, 'mode', 0o777), recursive, req);
 }
 
-Object.defineProperties(mkdir, {
-  [Symbol('recursive')]: {
-    value: true,
-    writable: false,
-    enumerable: false
-  }
+Object.defineProperty(mkdir, features, {
+  value: ['recursive'],
+  writable: false,
+  enumerable: false
 });
 
 function mkdirSync(path, options) {
@@ -774,12 +772,10 @@ function mkdirSync(path, options) {
   handleErrorFromBinding(ctx);
 }
 
-Object.defineProperties(mkdirSync, {
-  [Symbol('recursive')]: {
-    value: true,
-    writable: false,
-    enumerable: false
-  }
+Object.defineProperty(mkdirSync, features, {
+  value: ['recursive'],
+  writable: false,
+  enumerable: false
 });
 
 function readdir(path, options, callback) {

lib/util.js

@@ -1472,6 +1472,7 @@ module.exports = exports = {
   callbackify,
   debuglog,
   deprecate,
+  features: Symbol('features'),
   format,
   formatWithOptions,
   getSystemErrorName,

test/parallel/test-fs-mkdir.js

@@ -24,6 +24,7 @@ const common = require('../common');
 const assert = require('assert');
 const fs = require('fs');
 const path = require('path');
+const { features } = require('util');
 
 const tmpdir = require('../common/tmpdir');
 tmpdir.refresh();
@@ -174,18 +175,10 @@ if (common.isMainThread && (common.isLinux || common.isOSX)) {
 
 // mkdirp and mkdirSyncp feature detection
 {
-  assert.strictEqual(Object.getOwnPropertySymbols(fs.mkdir).map((sym) => {
-    return sym.toString();
-  }).includes('Symbol(recursive)'), true);
-  assert.strictEqual(Object.getOwnPropertySymbols(fs.mkdirSync).map((sym) => {
-    return sym.toString();
-  }).includes('Symbol(recursive)'), true);
-  assert.strictEqual(Object.getOwnPropertySymbols(fs.mkdir).map((sym) => {
-    return sym.toString();
-  }).includes('Symbol(fhwdgads)'), false);
-  assert.strictEqual(Object.getOwnPropertySymbols(fs.mkdirSync).map((sym) => {
-    return sym.toString();
-  }).includes('Symbol(fhwdgads)'), false);
+  assert.strictEqual(fs.mkdir[features].includes('recursive'), true);
+  assert.strictEqual(fs.mkdir[features].includes('fhwdgads'), false);
+  assert.strictEqual(fs.mkdirSync[features].includes('recursive'), true);
+  assert.strictEqual(fs.mkdirSync[features].includes('fhwdgads'), false);
 }
 
 // Keep the event loop alive so the async mkdir() requests