powerShell optimizatio error handling

lib/util.js

@@ -218,24 +218,10 @@ function getWmic() {
 
 function powerShell(cmd) {
 
-  // helper function
-  function dispose(child) {
-    return new Promise((resolve, reject) => {
-      child.stdin.write('exit' + os.EOL);
-      process.nextTick(() => {
-        child.stdin.end()
-        child.kill();
-        resolve();
-      });
-    })
-  }
-
   let result = '';
 
   return new Promise((resolve, reject) => {
-
     process.nextTick(() => {
-
       try {
         const child = spawn('powershell.exe', ['-NoLogo', '-InputFormat', 'Text', '-NoExit', '-ExecutionPolicy', 'Unrestricted', '-Command', '-'], {
           stdio: 'pipe'
@@ -246,20 +232,24 @@ function powerShell(cmd) {
             result = result + data.toString('utf8');
           });
           child.stderr.on('data', function (data) {
-            dispose(child).then(resolve(result));
+            child.kill();
+            resolve(result);
           });
           child.on('close', function () {
-            dispose(child).then(resolve(result));
+            child.kill();
-            ;
+            resolve(result);
           });
           child.on('error', function () {
-            dispose(child).then(resolve(result));
+            child.kill();
+            resolve(result);
           });
-
           try {
             child.stdin.write(cmd + os.EOL);
+            child.stdin.write('exit' + os.EOL);
+            child.stdin.end()
           } catch (e) {
-            dispose(child).then(resolve(result));
+            child.kill();
+            resolve(result);
           }
         } else {
           resolve(result);
@@ -270,7 +260,6 @@ function powerShell(cmd) {
     });
   });
 }
-
 function getCodepage() {
   if (_windows) {
     if (!codepage) {