chore: Reduce amount of command args iterations

The happy case should be slightly faster that way when there are multiple arguments

Author: marcbachmann

lib/command.ts

@@ -154,6 +154,7 @@ export default class Command implements Respondable {
 
   private replyEncoding: BufferEncoding | null;
   private errorStack: Error;
+  private bufferMode: boolean;
   public args: CommandParameter[];
   private callback: CallbackFunction;
   private transformed = false;
@@ -270,14 +271,6 @@ export default class Command implements Respondable {
    * @public
    */
   public toWritable(_socket: object): string | Buffer {
-    let bufferMode = false;
-    for (const arg of this.args) {
-      if (arg instanceof Buffer) {
-        bufferMode = true;
-        break;
-      }
-    }
-
     let result;
     const commandStr =
       "*" +
@@ -287,10 +280,12 @@ export default class Command implements Respondable {
       "\r\n" +
       this.name +
       "\r\n";
-    if (bufferMode) {
+
+    if (this.bufferMode) {
       const buffers = new MixedBuffers();
       buffers.push(commandStr);
-      for (const arg of this.args) {
+      for (let i = 0; i < this.args.length; ++i) {
+        const arg = this.args[i];
         if (arg instanceof Buffer) {
           if (arg.length === 0) {
             buffers.push("$0\r\n\r\n");
@@ -312,7 +307,8 @@ export default class Command implements Respondable {
       result = buffers.toBuffer();
     } else {
       result = commandStr;
-      for (const arg of this.args) {
+      for (let i = 0; i < this.args.length; ++i) {
+        const arg = this.args[i];
         result +=
           "$" +
           Buffer.byteLength(arg as string | Buffer) +
@@ -327,7 +323,11 @@ export default class Command implements Respondable {
   stringifyArguments(): void {
     for (let i = 0; i < this.args.length; ++i) {
       const arg = this.args[i];
-      if (!(arg instanceof Buffer) && typeof arg !== "string") {
+      if (typeof arg === 'string') {
+        // buffers and strings don't need any transformation
+      } else if (arg instanceof Buffer) {
+        this.bufferMode = true;
+      } else {
         this.args[i] = toArg(arg);
       }
     }

lib/script.ts

@@ -58,7 +58,7 @@ export default class Script {
 
     const evalsha = new this.Command(
       "evalsha",
-      [this.sha].concat(args),
+      [this.sha, ...args],
       options
     );
     evalsha.isCustomCommand = true;
@@ -72,7 +72,7 @@ export default class Script {
       // in case it's not loaded yet on the connectionDo an eval as fallback, redis will hash and load it
       const resend = new this.Command(
         "evalsha",
-        [this.sha].concat(args),
+        [this.sha, ...args],
         options
       );
       resend.isCustomCommand = true;

lib/utils/Commander.ts

@@ -196,19 +196,8 @@ function generateScriptingFunction(
   script: Script,
   encoding: unknown
 ) {
-  return function () {
-    let length = arguments.length;
-    const lastArgIndex = length - 1;
-    let callback = arguments[lastArgIndex];
-    if (typeof callback !== "function") {
-      callback = undefined;
-    } else {
-      length = lastArgIndex;
-    }
-    const args = new Array(length);
-    for (let i = 0; i < length; i++) {
-      args[i] = arguments[i];
-    }
+  return function (...args) {
+    const callback = typeof args[args.length - 1] === "function" ? args.pop() : undefined;
 
     let options;
     if (this.options.dropBufferSupport) {