Remove a specific item from an Array in JavaScript. All instances of that item will be removed

removeItem.js

// Adding to the prototype so it can be used like a normal array method
Array.prototype.removeItem = function removeItem(item) {
  const formattedItem = typeof item === 'string' ? item.trim().toLowerCase() : item;
  const formattedItems = this.map((currentItem) => {
    if (typeof currentItem === 'string') {
      return currentItem.toLowerCase();
    };

    return currentItem;
  });

  if (formattedItems.indexOf(formattedItem)  === -1) {
   throw new Error('Item not found');
  }

  const newArray = this.filter((currentItem) => {
    if (typeof currentItem === 'string') {
      return currentItem.toLowerCase() !== formattedItem
    }

    return currentItem !== formattedItem;
  });

  return newArray;
};

// USAGE
// strings
const names = ['Jane', 'John', 'Matthew', 'Mark'];
names.removeItem('jane');

// integers
const numbers = [12,14,15];
console.log(numbers.removeItem(14));

// floats
const floats = [0.9, 0.2, 0.25];
console.log(floats.removeItem(0.9));