Remove an item from a copy of an array without removing it from the original array

Question

How can I remove an object from a copy of an array without removing it from the original?

I have a global variable :

    var userTrickList = [];

And inside a function, I make a copy of that global array :

    var tempUserTrickList = userTrickList;

Then I use the removeItem function that I created to remove a certain object.

    removeItem(considerTrick.IDName, tempUserTrickList);


    function removeItem(item, list) {
        //takes a string as 'item', finds in the array as 'list', 
        //then removes it from the list.
        for(var i = 0; i < list.length; i++)
        {
            if(item === list[i])
            {
                list.splice(i,1);
            }
        }
    }

My problem is, this function removes it from the userTrickList too.

Any ideas? It's definitely a problem in "removeItem(considerTrick.IDName, tempUserTrickList);", but I can't think of a solution.

Answer 1

Use .slice(0) to clone an array.

var tempUserTrickList = userTrickList.slice(0);

Credits: http://davidwalsh.name/javascript-clone-array

Answer 2

use this function for your requirement

function removeElementFromArray(data,target) {
var temp=new Array();   
for ( var i = 0; i < data.length; i++) {
    if(data[i]!=target){
        temp.push(data[i]);
    }
}
return temp; }

here data is original array and target is the element you want to remove from array this function will return array without containing the removed item.

Answer 3

Try, It copy the original array

var tempUserTrickList = JSON.parse(JSON.stringify(userTrickList));

Demo CopyArray

Answer 4

for (i = 0, l = arr.length; i < l; i++) {
  if (arr[i] === item) {
    arr.splice(i, 1);
    i -= 1;
    l -= 1;
  }
}

Answer 5

Daniel's method of cloning an array is absolutely correct, but since I don't see an ES6-oriented answer, I'll offer up an alternative solution:

We can just as easily use the spread operator to clone an array, so we don't have to use the slice call.

const arr = [1, 2, 3];
const copy = [...arr];
copy.pop();
console.log(arr);  // returns [1, 2, 3]
console.log(copy); // returns [1, 2]