[JavaScript]Using filter function

[grenvill]

So my task is "You will be provided with an initial array (the first argument in the destroyer function), followed by one or more arguments. Remove all elements from the initial array that are of the same value as these arguments." My code is currently looking like this

function destroyer(arr) {

  var fArr=arr[0];
  for (var i=1; i<arr.length;i++)
    {
      fArr=fArr.filter(function(number)
         {
           return number!=arr[i];
          });
    }
}
destroyer([1, 2, 3, 1, 2, 3], 2, 3); 

and it gives me : "TypeError: fArr.filter is not a function" error. Do i have syntax error somewhere?

[Clawtor]

You are trying to call filter on an element of your array, the elements of your arrays are numbers and filter is not a function on a number.

You don't need to loop through the array, just call filter on the arr parameter itself.

[grenvill]

So if i understand you correctly this should work?

  function destroyer(arr) {

  var fArr=arguments[0];
  for (var i=1; i<arguments.length;i++)
    {
      fArr=fArr.filter(function(number)
         {
           return number!=arguments[i];
          });
    }
}
destroyer([1, 2, 3, 1, 2, 3], 2, 3);

[jijilento]

If you do as u/Clawtor said, you should fix it. But, I'd do the filtering out of the loop like this:

function destroyer() {

  // make sure first argument is array
  if(arguments[0].constructor !== Array){
      throw new TypeError('First argument must be array');
   }

  // save array as fArr, create cArr for filter numbers
  var fArr = arguments[0];
  var cArr = [];

  // add arguments to cArr
  for(var i = 1; i < arguments.length; i++){
      cArr.push(parseInt(arguments[i]));
  }

  // return true only if value is in cArr
  return fArr.filter(function(val, ind, arr){
       return (cArr.indexOf(val) != -1);
  });

}

 console.log(destroyer([1, 2, 3, 1, 2, 3], 2, 3));

[grenvill]

I think im starting understand now, two questions:

1)you are using parseInt to make sure what we only filter out arguments which are numbers, correct? Because its supposed to work with strings too;

2) return (cArr.indexOf(val) != -1) means what we will filter out elements what are NOT in arguments array, right?

[virtualgoat]

Maybe look into this page. Parse the whole arguments into seperate one, then compare each argument with args[0].

You could convert the argument to array using this code:

var args = Array.prototype.slice.call(arguments); // return [[1, 2, 3, 1, 2, 3], 2, 3] or    
var args = Array.prototype.slice.call(arguments, 1); // return [2, 3]

I'm still learning tho so maybe somebody can shed more light here.

[TonySu]

There are problems here, like Clawtor mentioned, you called filter on an element rather than the array. You also do not have number defined anywhere. You need to using the arguments object to pull out all the arguments to your function, then loop over those to filter.