perf: Serialize error stack only when needed (#1359)

* Optimize error stack extraction

* Add benchmark

Author: aivopaas

benchmarks/errorStack.ts

@@ -0,0 +1,38 @@
+import { cronometro } from "cronometro";
+import Redis from "../lib/redis";
+
+let redis;
+
+cronometro(
+  {
+    default: {
+      test() {
+        return redis.set("foo", "bar");
+      },
+      before(cb) {
+        redis = new Redis();
+        cb();
+      },
+      after(cb) {
+        redis.quit();
+        cb();
+      },
+    },
+    "showFriendlyErrorStack=true": {
+      test() {
+        return redis.set("foo", "bar");
+      },
+      before(cb) {
+        redis = new Redis({ showFriendlyErrorStack: true });
+        cb();
+      },
+      after(cb) {
+        redis.quit();
+        cb();
+      },
+    },
+  },
+  {
+    print: { compare: true },
+  }
+);

lib/command.ts

@@ -20,7 +20,7 @@ interface ICommandOptions {
    * @memberof ICommandOptions
    */
   replyEncoding?: string | null;
-  errorStack?: string;
+  errorStack?: Error;
   keyPrefix?: string;
   /**
    * Force the command to be readOnly so it will also execute on slaves
@@ -149,7 +149,7 @@ export default class Command implements ICommand {
   public isReadOnly?: boolean;
 
   private replyEncoding: string | null;
-  private errorStack: string;
+  private errorStack: Error;
   public args: CommandParameter[];
   private callback: CallbackFunction;
   private transformed = false;
@@ -215,7 +215,7 @@ export default class Command implements ICommand {
       this.resolve = this._convertValue(resolve);
       if (this.errorStack) {
         this.reject = (err) => {
-          reject(optimizeErrorStack(err, this.errorStack, __dirname));
+          reject(optimizeErrorStack(err, this.errorStack.stack, __dirname));
         };
       } else {
         this.reject = reject;

lib/commander.ts

@@ -160,9 +160,7 @@ function generateFunction(
     }
 
     const options = {
-      errorStack: this.options.showFriendlyErrorStack
-        ? new Error().stack
-        : undefined,
+      errorStack: this.options.showFriendlyErrorStack ? new Error() : undefined,
       keyPrefix: this.options.keyPrefix,
       replyEncoding: _encoding,
     };
@@ -226,7 +224,7 @@ function generateScriptingFunction(
     }
 
     if (this.options.showFriendlyErrorStack) {
-      options.errorStack = new Error().stack;
+      options.errorStack = new Error();
     }
 
     // No auto pipeline, use regular command sending