lib: created isValidCallback helper

check for callback function is moved to a separate function.
This piece of code is being shared by other entities as well.

Author: yashLadha

lib/internal/validators.js

@@ -14,7 +14,8 @@ const {
     ERR_INVALID_ARG_TYPE,
     ERR_INVALID_ARG_VALUE,
     ERR_OUT_OF_RANGE,
-    ERR_UNKNOWN_SIGNAL
+    ERR_UNKNOWN_SIGNAL,
+    ERR_INVALID_CALLBACK,
   }
 } = require('internal/errors');
 const { normalizeEncoding } = require('internal/util');
@@ -194,6 +195,11 @@ function validatePort(port, name = 'Port', { allowZero = true } = {}) {
   return port | 0;
 }
 
+const validateCallback = hideStackFrames((callback) => {
+  if (typeof callback !== 'function')
+    throw new ERR_INVALID_CALLBACK(callback);
+});
+
 module.exports = {
   isInt32,
   isUint32,
@@ -210,4 +216,5 @@ module.exports = {
   validateSignalName,
   validateString,
   validateUint32,
+  validateCallback,
 };

lib/timers.js

@@ -53,8 +53,8 @@ const {
   promisify: { custom: customPromisify },
   deprecate
 } = require('internal/util');
-const { ERR_INVALID_CALLBACK } = require('internal/errors').codes;
 const debug = require('internal/util/debuglog').debuglog('timer');
+const { validateCallback } = require('internal/validators');
 
 const {
   destroyHooksExist,
@@ -118,9 +118,7 @@ function enroll(item, msecs) {
 
 
 function setTimeout(callback, after, arg1, arg2, arg3) {
-  if (typeof callback !== 'function') {
-    throw new ERR_INVALID_CALLBACK(callback);
-  }
+  validateCallback(callback);
 
   let i, args;
   switch (arguments.length) {
@@ -165,9 +163,7 @@ function clearTimeout(timer) {
 }
 
 function setInterval(callback, repeat, arg1, arg2, arg3) {
-  if (typeof callback !== 'function') {
-    throw new ERR_INVALID_CALLBACK(callback);
-  }
+  validateCallback(callback);
 
   let i, args;
   switch (arguments.length) {
@@ -249,9 +245,7 @@ const Immediate = class Immediate {
 };
 
 function setImmediate(callback, arg1, arg2, arg3) {
-  if (typeof callback !== 'function') {
-    throw new ERR_INVALID_CALLBACK(callback);
-  }
+  validateCallback(callback);
 
   let i, args;
   switch (arguments.length) {