在freecodecamp中使用Javascript filter（）函数时出错

Question

function destroyer(arr) {

var arry=[];


for(var i=1;i<arr.length;i++)
{
  arr[0] = arr[0].filter(cc => cc != arr[i]);
}
return arry;
}

destroyer([1, 2, 3, 1, 2, 3], 2, 3);

I basically have to return all the elements of the first sub-array which arent present in the rest of array.

Its displaying "arr[0].filter isnt a function. destroyer([1, 2, 3, 1, 2, 3], 2, 3) should return [1, 1]. I basically have to return all the elements of the first sub-array which arent present in the array.

Answer 1

You aren't doing anything with the other arguments provided to the destroyer function - you have to test those arguments against arr , you shouldn't be testing arr against itself.

 function destroyer() { const [arr, ...excludeArr] = arguments; return arr.filter(elm => !excludeArr.includes(elm)); } console.log( destroyer([1, 2, 3, 1, 2, 3], 2, 3) ); 

Answer 2

 function destroyer(arr, x, y) { return arr.filter(item => (item != x) && (item != y)) } console.log(destroyer([1, 2, 3, 1, 2, 3], 2, 3)) 

Answer 3

 const destroyer = (arr, ...args) => { return arr.filter(item => args.indexOf(item) < 0); }; const result = destroyer([1, 2, 3, 1, 2, 3], 2, 3); console.log(result); 

Answer 4

You forgot to call your method using the array. you have to surround it with another pair of [] .

You can simply return the filtered arr[0] to get what you want.

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

Answer 5

as you said you should filter first subarray but you are sending only 1 array with int values and other values as argument, the actual usage of this function should be

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