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

doc/api/fs.md

@@ -2086,6 +2086,14 @@ fs.mkdir('/tmp/a/apple', { recursive: true }, (err) => {
 });
 ```
 
+The `util.features` symbol can be used to feature detect if
+recursion is available.
+
+```js
+fs.mkdir[util.features].recursive;
+// true
+```
+
 See also: mkdir(2).
 
 ## fs.mkdirSync(path[, options])
@@ -2106,6 +2114,14 @@ changes:
 Synchronously creates a directory. Returns `undefined`.
 This is the synchronous version of [`fs.mkdir()`][].
 
+The `util.features` symbol can be used to feature detect if
+recursion is available.
+
+```js
+fs.mkdirSync[util.features].recursive;
+// true
+```
+
 See also: mkdir(2).
 
 ## fs.mkdtemp(prefix[, options], callback)

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');
@@ -745,6 +745,14 @@ function mkdir(path, options, callback) {
                 validateMode(mode, 'mode', 0o777), recursive, req);
 }
 
+Object.defineProperty(mkdir, features, {
+  value: {
+    recursive: true
+  },
+  writable: false,
+  enumerable: false
+});
+
 function mkdirSync(path, options) {
   if (typeof options === 'number' || typeof options === 'string') {
     options = { mode: options };
@@ -766,6 +774,14 @@ function mkdirSync(path, options) {
   handleErrorFromBinding(ctx);
 }
 
+Object.defineProperty(mkdirSync, features, {
+  value: {
+    recursive: true
+  },
+  writable: false,
+  enumerable: false
+});
+
 function readdir(path, options, callback) {
   callback = makeCallback(typeof options === 'function' ? options : callback);
   options = getOptions(options, {});

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();
@@ -172,6 +173,14 @@ if (common.isMainThread && (common.isLinux || common.isOSX)) {
   });
 }
 
+// mkdirp and mkdirSyncp feature detection
+{
+  assert.strictEqual(fs.mkdir[features].recursive, true);
+  assert.strictEqual(fs.mkdir[features].fhwdgads, undefined);
+  assert.strictEqual(fs.mkdirSync[features].recursive, true);
+  assert.strictEqual(fs.mkdirSync[features].fhwdgads, undefined);
+}
+
 // Keep the event loop alive so the async mkdir() requests
 // have a chance to run (since they don't ref the event loop).
 process.nextTick(() => {});