javascriptarraysfilterinteger

I get [1,15], instead of [1,0,15]. JavaScript filter

Create a function that takes a list of non-negative integers and strings and returns a new list with the strings filtered out. When I pass [1,'a','b',0,15], it returns [1,15] instead of [1,0,15]. Please suggest any corrections.

function filter_list(l) {
  // Return a new array with the strings filtered out
  var filt = l.filter(function(x) {
    if (typeof(x) === 'number')
      return x;
  });
  return filt;
}

Solution

  • 0 is falsey, and if the value returned by the filter callback is falsey, the item being iterated over will not be included in the final array. Simply return typeof x === 'number' instead:

    function filter_list(l) {
  return l.filter(x => typeof x === 'number');
}
console.log(filter_list([1, 'a', 'b', 0, 15]));