Callback Functions

A callback is simply a function that’s passed in as a parameter to another function and then it’s ran inside the function body. So whenever we did a foreach on an array when we do array for each and then we pass in function. That’s actually a callback.

const posts = [
    { title: 'Post One', body: 'This is post one' }, 
    { title: 'Post Two', body: 'This is post two' }
]

function createPost(post, callback){
    setTimeout(function(){
        posts.push(post);
        callback();
    }, 2000);
}

function getPost(){
    setTimeout(function(){
        let output = '';
        posts.forEach(function(post){
            output += `<li>${post.title}</li>`;
        });
        document.body.innerHTML = output;
    }, 1000);
}
createPost({ title: 'Post Three', body: 'This is post Three'}, getPost);

getPost();