Code snippet to demonstrate callback functions(async run) pattern

nodeCallbackDemo.js

const addFunction = (a, b, callback) => {
    setTimeout(() => {
        const sum = a+b
        callback(sum)
    },1000)
}

addFunction(1, 2, (sum) => {
    console.log(sum)
})

console.log("This line prints first before computing sum...")

// to run this file -> node nodeCallbackDemo.js