Day 4: Functions Calling Functions & Callbacks

Daily Objective

Compose modular functions and understand higher-order functions that accept callbacks.

1. Callback Functions

A callback is a function passed into another function as an argument:

function processTransaction(amount, callback) {
  console.log(`Processing payment of $${amount}...`);
  callback(amount);
}

const sendNotification = amt => {
  console.log(`Receipt emailed for $${amt}`);
};

processTransaction(75, sendNotification);

Daily Hands-on Practice (70%)

1. Write a calculate(a, b, operationCallback) function that accepts an operation function (add, subtract, etc.) and returns the result.