fix: support directories named __proto__

src/__tests__/volume/mkdirSync.test.ts

@@ -1,4 +1,5 @@
 import { create } from '../util';
+import type Stats from '../../Stats';
 
 describe('mkdirSync', () => {
   it('can create a directory', () => {
@@ -50,4 +51,22 @@ describe('mkdirSync', () => {
     expect(error).toBeInstanceOf(Error);
     expect(error.message).toMatchSnapshot();
   });
+
+  /**
+   * See issue #938
+   * https://github.com/streamich/memfs/issues/938
+   */
+  it('can create a directory with name "__proto__"', () => {
+    const vol = create();
+
+    vol.mkdirSync('/__proto__');
+    let isDirectory = false;
+    try {
+      isDirectory = vol.statSync('/__proto__').isDirectory();
+    } catch {
+      // ignore
+    }
+
+    expect(isDirectory).toBe(true);
+  });
 });

src/node.ts

@@ -308,7 +308,7 @@ export class Link extends EventEmitter {
 
   parent: Link;
 
-  children: { [child: string]: Link | undefined } = {};
+  children = new Map<string, Link | undefined>();
 
   // Path to this node as Array: ['usr', 'bin', 'node'].
   private _steps: string[] = [];
@@ -331,7 +331,7 @@ export class Link extends EventEmitter {
   // Recursively sync children steps, e.g. in case of dir rename
   set steps(val) {
     this._steps = val;
-    for (const [child, link] of Object.entries(this.children)) {
+    for (const [child, link] of this.children.entries()) {
       if (child === '.' || child === '..') {
         continue;
       }
@@ -361,7 +361,7 @@ export class Link extends EventEmitter {
     link.setNode(node);
 
     if (node.isDirectory()) {
-      link.children['.'] = link;
+      link.children.set('.', link);
       link.getNode().nlink++;
     }
 
@@ -371,13 +371,13 @@ export class Link extends EventEmitter {
   }
 
   setChild(name: string, link: Link = new Link(this.vol, this, name)): Link {
-    this.children[name] = link;
+    this.children.set(name, link);
     link.parent = this;
     this.length++;
 
     const node = link.getNode();
     if (node.isDirectory()) {
-      link.children['..'] = this;
+      link.children.set('..', this);
       this.getNode().nlink++;
     }
 
@@ -390,10 +390,10 @@ export class Link extends EventEmitter {
   deleteChild(link: Link) {
     const node = link.getNode();
     if (node.isDirectory()) {
-      delete link.children['..'];
+      link.children.delete('..');
       this.getNode().nlink--;
     }
-    delete this.children[link.getName()];
+    this.children.delete(link.getName());
     this.length--;
 
     this.getNode().mtime = new Date();
@@ -402,9 +402,7 @@ export class Link extends EventEmitter {
 
   getChild(name: string): Link | undefined {
     this.getNode().mtime = new Date();
-    if (Object.hasOwnProperty.call(this.children, name)) {
-      return this.children[name];
-    }
+    return this.children.get(name);
   }
 
   getPath(): string {
@@ -446,7 +444,7 @@ export class Link extends EventEmitter {
     return {
       steps: this.steps,
       ino: this.ino,
-      children: Object.keys(this.children),
+      children: Array.from(this.children.keys()),
     };
   }
 

src/volume.ts

@@ -528,11 +528,13 @@ export class Volume implements FsCallbackApi {
     let children = link.children;
 
     if (link.getNode().isFile()) {
-      children = { [link.getName()]: link.parent.getChild(link.getName()) };
+      children = new Map([
+        [link.getName(), link.parent.getChild(link.getName())]
+      ]);
       link = link.parent;
     }
 
-    for (const name in children) {
+    for (const name of children.keys()) {
       if (name === '.' || name === '..') {
         continue;
       }
@@ -568,7 +570,7 @@ export class Volume implements FsCallbackApi {
     const links: Link[] = [];
 
     if (paths) {
-      if (!(paths instanceof Array)) paths = [paths];
+      if (!Array.isArray(paths)) paths = [paths];
       for (const path of paths) {
         const filename = pathToFilename(path);
         const link = this.getResolvedLink(filename);
@@ -1346,7 +1348,7 @@ export class Volume implements FsCallbackApi {
 
     if (options.withFileTypes) {
       const list: Dirent[] = [];
-      for (const name in link.children) {
+      for (const name of link.children.keys()) {
         const child = link.getChild(name);
 
         if (!child || name === '.' || name === '..') {
@@ -1365,7 +1367,7 @@ export class Volume implements FsCallbackApi {
     }
 
     const list: TDataOut[] = [];
-    for (const name in link.children) {
+    for (const name of link.children.keys()) {
       if (name === '.' || name === '..') {
         continue;
       }
@@ -2406,23 +2408,23 @@ export class FSWatcher extends EventEmitter {
             removers.forEach(r => r());
             this._listenerRemovers.delete(ino);
           }
-          Object.entries(curLink.children).forEach(([name, childLink]) => {
+          for (const [name, childLink] of curLink.children.entries()) {
             if (childLink && name !== '.' && name !== '..') {
               removeLinkNodeListeners(childLink);
             }
-          });
+          };
         };
         removeLinkNodeListeners(l);
 
         this.emit('change', 'rename', relative(this._filename, l.getPath()));
       };
 
       // children nodes changed
-      Object.entries(link.children).forEach(([name, childLink]) => {
+      for (const [name, childLink] of link.children.entries()) {
         if (childLink && name !== '.' && name !== '..') {
           watchLinkNodeChanged(childLink);
         }
-      });
+      };
       // link children add/remove
       link.on('child:add', onLinkChildAdd);
       link.on('child:delete', onLinkChildDelete);
@@ -2434,11 +2436,11 @@ export class FSWatcher extends EventEmitter {
       });
 
       if (recursive) {
-        Object.entries(link.children).forEach(([name, childLink]) => {
+        for (const [name, childLink] of link.children.entries()) {
           if (childLink && name !== '.' && name !== '..') {
             watchLinkChildrenChanged(childLink);
           }
-        });
+        };
       }
     };
     watchLinkNodeChanged(this._link);