export local array value to global value

Question

I am trying to return the value of array by using console.log(array); it return empty value []. any suggestion is greatly appreciate it.

var array = [];
var maxLength = 3;
var delay = 250; //I shortened your delay
var ticker = {}; //I'll use this to simulate your ticker object

var looper = setInterval(function() { 
      ticker.BNBBTC = Math.random(); //populating your ticker property w/random value

      if (array.length < maxLength) {
         array.push(ticker.BNBBTC);
      } else {
         console.log("Stopping the looper.");
         clearInterval(looper);
         console.log("Here are the contents of array");
         console.log(array);
      }
}, delay);

Answer 1

Here's how you could do it with a callback

const fn = callback => {
  var array = [];
  var maxLength = 3;
  var delay = 250; //I shortened your delay
  var ticker = {}; //I'll use this to simulate your ticker object

  var looper = setInterval(function() {
    ticker.BNBBTC = Math.random(); //populating your ticker property w/random value

    if (array.length < maxLength) {
      array.push(ticker.BNBBTC);
    } else {
      console.log("Stopping the looper.");
      clearInterval(looper);
      console.log("Here are the contents of array");
      callback(array);
    }
  }, delay);
};
fn(result => {
  console.log(result);
})

or with a Promise

const fn = () => new Promise(resolve => {
  var array = [];
  var maxLength = 3;
  var delay = 250; //I shortened your delay
  var ticker = {}; //I'll use this to simulate your ticker object

  var looper = setInterval(function() {
    ticker.BNBBTC = Math.random(); //populating your ticker property w/random value

    if (array.length < maxLength) {
      array.push(ticker.BNBBTC);
    } else {
      console.log("Stopping the looper.");
      clearInterval(looper);
      console.log("Here are the contents of array");
      resolve(array);
    }
  }, delay);
});
fn().then(console.log)

You'll notice with both of these methods there's no reason to "pollute" the global namespace - something that you should be avoiding as much as possible in modern javascript - the only global in either case is the const fn