Pass an extra argument to a callback function

Question

I have a function callWithMagic which takes a callback function as a parameter and calls it with one argument.

const callWithMagic = callback =&         


        

Answer 1

You can bind argument object to callback function:

var varObject = {var1: "findButton", var2: true};

function cbFunc() {
    console.log(this.var1+ ":" + this.var2);
}

//Example callback
datatable.ajax.reload(cbFunc.bind(varObject));

Answer 2

You could use an anonymus function

something like

session.sub('Hello', function(){marketEvents(your args);});

Answer 3

You can create a function which calls the marketEvent function. No need to complicate things

session.sub('Hello', function(args, kwargs) {
    marketEvent(args, kwargs, 'my custom data');
});

otherwise you can do this:

var mrktEvent = function(customArgs) {
    return function(args, kwargs) { 
        marketEvent(args, kwargs, customArgs) 
    };
}

session.sub('Hello', mrktEvent("customEvent"));

Answer 4

Just create a wrapper callback:

callWithMagic(function(magic) {
  return processMagic(magic, 42);
});

Or using ECMAScript 6 arrow functions:

callWithMagic(magic => processMagic(magic, 42));