Do something within a JavaScript array for loop

Question

I am trying to figure out a way of how to loop through an array, do something with that array[index] pause function for x seconds and move to next index in that array.

That is what I achieved so far. It prints out the whole array, but I need it to print out only one value, do something with it, then proceed to the next one and so on.

var destinations = ['Greece', 'Maldives', 'Croatia', 'Spain'];

var index = 0;

for (index = 0; index < destinations.length; index++){
  console.log(destinations[index]);
};

So... where are you stuck? What are you trying to do? What problems did you run into? — tymeJV
– tymeJV, Commented Feb 20, 2019 at 18:40
@tymeJV I need to loop through this array, grab 1 value at the time, use it, then grab the next one and so on. On top of that I need to pause this function each time it grabs a value, so it is not spitting all of the results at once, but one after the other — Durianix
– Durianix, Commented Feb 20, 2019 at 18:43
Have a look at the forEach function there is great documention on mdn var destinations = ['Greece', 'Maldives', 'Croatia', 'Spain']; destinations.forEach(function(element, i) { // do something to each value console.log(element, i); }); — David Dacruz
– David Dacruz, Commented Feb 20, 2019 at 18:47

Nina Scholz · Accepted Answer · 2019-02-20 19:31:02Z

2

You could take the iteration protocols with an implementation of Symbol.iterator in Array#[@@iterator]() and iterate until no more elements are available.

var destinations = ['Greece', 'Maldives', 'Croatia', 'Spain'],
    gen = destinations[Symbol.iterator]();
    interval = setInterval(function () {
        var g = gen.next();
        if (g.done) {
            clearInterval(interval);
            return;
        }
        console.log(g.value);
    }, 1000);

edited Feb 20, 2019 at 19:31

answered Feb 20, 2019 at 18:44

Nina Scholz

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Comments

Manuel Otto · Accepted Answer · 2019-02-20 18:44:03Z

0

You can use setTimeout to do this.

var time_between_steps = 1000
var destinations = ['Greece', 'Maldives', 'Croatia', 'Spain']
var index = 0

function nextItem(){
  // do things here with destinations[index]
  console.log(destinations[index])
  
  index++
  
  // if we have not yet reached the end of the array, run nextItem again after time_between_steps
  if(index<=destinations.length-1)
    setTimeout(nextItem,time_between_steps)
}


nextItem()

answered Feb 20, 2019 at 18:44

Manuel Otto

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Comments

mmsilviu · Accepted Answer · 2019-02-20 19:18:02Z

0

setTimeout can be used here:

Basically, you can define a method processItem and call it with the current parameter. Also the delay can be set with a variable.

After the delay, the method is called with a parameter.

var delay = 1000; // 1 sec
var destinations = ['Greece', 'Maldives', 'Croatia', 'Spain'];
var index = 0;

function processItem(item){
  console.log("Item " + item);
  // do stuff
}

function iterate(index){
  processItem(destinations[index]);
  index++;
  if (index < destinations.length){
   setTimeout(iterate, delay, index);
  }
}

iterate(index);

edited Feb 20, 2019 at 19:18

answered Feb 20, 2019 at 18:54

mmsilviu

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