feat(node): patch most fs methods (#438)

lib/node/fs.ts

@@ -0,0 +1,56 @@
+import {bindArguments} from '../common/utils';
+
+let fs;
+try {
+  fs = require('fs');
+} catch (err) {}
+
+// TODO(alxhub): Patch `watch` and `unwatchFile`.
+const TO_PATCH = [
+  'access',
+  'appendFile',
+  'chmod',
+  'chown',
+  'close',
+  'exists',
+  'fchmod',
+  'fchown',
+  'fdatasync',
+  'fstat',
+  'fsync',
+  'ftruncate',
+  'futimes',
+  'lchmod',
+  'lchown',
+  'link',
+  'lstat',
+  'mkdir',
+  'mkdtemp',
+  'open',
+  'read',
+  'readdir',
+  'readFile',
+  'readlink',
+  'realpath',
+  'rename',
+  'rmdir',
+  'stat',
+  'symlink',
+  'truncate',
+  'unlink',
+  'utimes',
+  'write',
+  'writeFile',
+];
+
+if (fs) {
+  TO_PATCH
+    .filter(name => !!fs[name] && typeof fs[name] === 'function')
+    .forEach(name => {
+      fs[name] = ((delegate: Function) => {
+        return function() {
+          return delegate.apply(this, bindArguments(<any>arguments, 'fs.' + name));
+        };
+      })(fs[name]);
+    });
+}

lib/node/node.ts

@@ -2,6 +2,7 @@ import '../zone';
 import {patchTimer} from '../common/timers';
 
 import './events';
+import './fs';
 
 const set = 'set';
 const clear = 'clear';

test/node/fs.spec.ts

@@ -0,0 +1,13 @@
+import {exists} from 'fs';
+
+describe('nodejs file system', () => {
+  it('has patched exists()', (done) => {
+    const zoneA = Zone.current.fork({ name: 'A' });
+    zoneA.run(() => {
+      exists('testfile', (_) => {
+        expect(Zone.current.name).toBe(zoneA.name);
+        done();
+      });
+    });
+  });
+});

test/node_tests.ts

@@ -1 +1,2 @@
-import './node/events.spec';
+import './node/events.spec';
+import './node/fs.spec';