Condensing a sparse array in Javascript?

Question

I have an array of elements where the entries are sparse. How can I easily condense the sparse array into a dense array so that I don\'t have to keep checking for null and

Answer 1

In vanilla JS, works on all browsers:

function filt(a) { 
 var b = []; 
 for(var i = 0;i < a.length;i++) { 
  if (a[i] !== undefined && a[i] !== null) { 
   b.push(a[i]); 
  }
 } 
 return b; 
}

> filt([1,undefined,3])
[1, 3]