Pass a paramerter to call back function in nodejs

Question

I'm new to nodejs and i need to know how to pass the parameter to callback function.

function scheduler(key, cron, callback){

  //cron-job-manager
  manager.add('key', '* 30 * * * *', callback)
}

function callback(key,cron){
 console.log(cron);
}

schdeduler("key", " * * * * *", callback);

Thanks in advance.

http://stackoverflow.com/questions/3458553/javascript-passing-parameters-to-a-callback-function — vidriduch, Apr 10 '15 at 09:45
Still i dont under stand the solution . can you please help me . — Devaraj, Apr 10 '15 at 09:53

phts · Accepted Answer · 2015-04-10T10:14:09.523

You can use a closure for your callback. You need to move callback function inside scheduler:

function scheduler(key, cron, callback){

  function callback() {
    console.log(key);
    console.log(cron);
  }

  //cron-job-manager
  manager.add(key, cron, callback)
}

schdeduler("key", " * * * * *", callback);

OR use bind:

function scheduler(key, cron, callback){

  //cron-job-manager
  manager.add(key, cron, callback.bind(this, key, cron))
}

function callback(key, cron) {
  console.log(key);
  console.log(cron);
}

schdeduler("key", " * * * * *", callback);

score 0 · Answer 2 · answered Apr 10 '15 at 10:15

as per the comment in your cese it would be:

function callback(key, cron) {
    console.log(key + ", " + cron);
}

function scheduler(key, cron, callback) {
    //manager.add('key', '* 30 * * * *', callback);
    callback();
}

scheduler("key", " * * * * *", function() {
    callback("key", " * * * * *");
});

Pass a paramerter to call back function in nodejs

2 Answers2