CODEWITHSUNDEEP
javascript
Chris
Chris

Reputation: 35

Difference between a callback and helper function

How are callback functions different from a helper function in javascript? if they are both accepting functions as arguments?

Upvotes: 1

Views: 1304

Answers (3)

Muhammad
Muhammad

Reputation: 7324

There nothing like callback function, it just refers to the function(named function) or anonymous function that is being called by a function or piece of code once it transitions to another state or after an event occurs.

Upvotes: 0

Drew Reese
Drew Reese

Reputation: 202836

They are both functions, but the difference I suppose is how they are referenced and/or used.

Helper functions are just called "whenever" when they are in scope. Callbacks are typically passed elsewhere and invoked with some parameters.

I hope the below snippet explains it.

// Just some function, what does it do?
const someFunction = (...args) => console.log("I'm a helper function", ...args);

const useAsHelperFunction = () => {
  // Called directly
  someFunction('used as helper function');
};

const useAsCallback = callback => {
  // invoking callback
  callback('used as callback function');
};

useAsHelperFunction();

useAsCallback(someFunction);

Upvotes: 0

Nikhil Goyal
Nikhil Goyal

Reputation: 1973

Callbacks are the functions that are passed as a function argument and are performed after a particular event such as resolving of a promise.

Helper functions are the normal functions that are called at any point of time when the code execution is taking place. Mostly, helper functions are wrapped inside another function.

Example of callback function:

const fun = (callback) => {
  setTimeout(callback, 3000);
};

fun(() => {
  console.log('callback function');
});

Example of helper function:

const factorialOfNNumbers = (...numbers) => {
    const helperFact = (n) => {
      if (n ===1 || n === 0)
        return n;

      return n * helperFact(n-1);
    };

  return numbers.map(n => helperFact(n));
};

console.log(factorialOfNNumbers(2, 3, 4));

Upvotes: 3

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