CODEWITHSUNDEEP
javascriptnode.jsfunctioncallbackstore
Etgar
Etgar

Reputation: 5924

Getting code from callback or storing callbacks in Javascript (Node.js)

I am trying to store callbacks in my database, and use them later from another session.

Is it possible?

Lets make some code for example:

// One session
var callback = () => {
  console.log("Hey! This is a callback!");
}

db.store("myCallback", callback);

// Another session
db.get("myCallback")(); // Output: "Hey! This is a callback!"

EDIT - Just to clarify my context, we can refer to this question: Question

Upvotes: 2

Views: 620

Answers (3)

theRemix
theRemix

Reputation: 2224

It would work best to store the parts if the callback functions that differ.

var callbackParams = { 
  message : "Hey! This is a callback!"
}
db.store("myCallback", callbackParams); 
// Another session 
var handleCallback = (params) => {
    console.log(params.message);
}
handleCallback(db.get("myCallback"));

The worst way is to use eval. Do not use eval as it could be easily exploitable leaving your program and system vulnerable for easy attacks.

Upvotes: 1

clabe45
clabe45

Reputation: 2454

You could use the javascript Function class.

As Alex Blex said, to implement this, you would have to store each callback as a string of javascript code in the database, and then retrieve it as a string. You pass this in as an argument for the Function(...) constructor.

That being said, this isn't a very efficient way of doing things. If you could store the result of the function in the data base, that would save a lot of space.

Upvotes: 2

EvgenyKolyakov
EvgenyKolyakov

Reputation: 3624

I'd make scene if you had something like this:

var myObj = new function() {
  // One session
  this.callback1 = () => {
    console.log("Hey! This is a callback1!");
  }
  this.callback2 = () => {
    console.log("Hey! This is a callback2!");
  }
}();



db.store("myCallback", "callback1");

// Another session
myObj[db.get("myCallback")](); // Output: "Hey! This is a callback1!"

Upvotes: 0

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