Nodejs callback next loop when function is finished

Question

Supposing we have a script that will execute a certain task for each row in an array.

function execute(err, array){
    loop(array, function(err,object){
         console.log(object)
         //do a certain task when it's finished get into the next object successively.
    });
}

function loop(array,callback){
    array.forEach(function(object){
         callback(null, object);
    });
}

function array(callback){
     callback(null, [1, 2, 3, 4, 5]);
}

setTimeout(function(){
    array(execute); 
}, 6000);

Questions:

• How to get into the next loop only after finishing the task?
• Is my function considered asynchronous ?

Answer 1

Try this:

function execute(err, array) {
    loop(array, function(err, object, next) {
         console.log(object);
         next(); // this will call recur inside loop function
    }, function() {
         console.log('All done');
    });
}

function loop(array, callback, finish) {
    var copy = array.slice();
    (function recur() {
        var item = copy.shift();
        if (typeof item !== 'undefined') {
            callback(null, item, recur);
        } else if (typeof finish == 'function') { 
            finish();
        }
    })();
}

No, your function is not asynchronous, but you call it asynchronously using setTimeout.

EDIT: changed if check

typeof item !== 'undefined'

so it will work when array contain falsy values like 0 or null.