`jQuery.getJSON()` function inside a for loop

Question

I have the following code which returns h=30 instead of each value inside the loop.

for (var h = 0; h < 31; h++) {
  $.getJSON('http://google.com/',
    function(data) {
      console.log('line ' + h);
    }
  )
};

What do I need to do to get loop values?

Answer 1

Make a closure with an IIFE

for (var h = 0; h < 31; h++) {
    (function(h) {
        $.getJSON('http://google.com/', function(data) {......
            console.log('line ' + h);
        })
    })(h)
};

That way, the value of h will be preserved for that iteration instead of being set to the last value by the time getJSON is called back