initBigArrayAsync.js

var THRESHOLD = 150, DELAY = 15;

function initBigArrayAsync(max, cb) {
    var r = [], i = 0;
    
    function init(startTime) {
        while (i < max) {
            if (new Date - startTime < THRESHOLD) {
                r[i++] = i;
            } else {
                setTimeout(function() {
                    init(new Date);
                }, DELAY);
                return;
            }
        }
        
        cb(r);
    }
    
    init(new Date);
}

setTimeout(function() {
  init(new Date);
}, DELAY);

could be

setTimeout(init, DELAY, new Date);