refactor: use async API (#3719)

Author: snitin315

lib/Server.js

@@ -545,11 +545,18 @@ class Server {
       if (!options.https.key || !options.https.cert) {
         const certificateDir = Server.findCacheDir();
         const certificatePath = path.join(certificateDir, "server.pem");
-        let certificateExists = fs.existsSync(certificatePath);
+        let certificateExists;
+
+        try {
+          const certificate = await fs.promises.stat(certificatePath);
+          certificateExists = certificate.isFile();
+        } catch {
+          certificateExists = false;
+        }
 
         if (certificateExists) {
           const certificateTtl = 1000 * 60 * 60 * 24;
-          const certificateStat = fs.statSync(certificatePath);
+          const certificateStat = await fs.promises.stat(certificatePath);
 
           const now = new Date();
 
@@ -561,7 +568,7 @@ class Server {
               "SSL Certificate is more than 30 days old. Removing..."
             );
 
-            del.sync([certificatePath], { force: true });
+            await del([certificatePath], { force: true });
 
             certificateExists = false;
           }
@@ -634,13 +641,18 @@ class Server {
             ],
           });
 
-          fs.mkdirSync(certificateDir, { recursive: true });
-          fs.writeFileSync(certificatePath, pems.private + pems.cert, {
-            encoding: "utf8",
-          });
+          await fs.promises.mkdir(certificateDir, { recursive: true });
+
+          await fs.promises.writeFile(
+            certificatePath,
+            pems.private + pems.cert,
+            {
+              encoding: "utf8",
+            }
+          );
         }
 
-        fakeCert = fs.readFileSync(certificatePath);
+        fakeCert = await fs.promises.readFile(certificatePath);
 
         this.logger.info(`SSL certificate: ${certificatePath}`);
       }
@@ -1158,7 +1170,7 @@ class Server {
     app.get("/__webpack_dev_server__/sockjs.bundle.js", (req, res) => {
       res.setHeader("Content-Type", "application/javascript");
 
-      const { createReadStream } = require("graceful-fs");
+      const { createReadStream } = fs;
       const clientPath = path.join(__dirname, "..", "client");
 
       createReadStream(
@@ -2075,7 +2087,7 @@ class Server {
       // chmod 666 (rw rw rw)
       const READ_WRITE = 438;
 
-      fs.chmodSync(this.options.ipc, READ_WRITE);
+      await fs.promises.chmod(this.options.ipc, READ_WRITE);
     }
 
     if (this.options.webSocketServer) {