与另一个数组相等的数组并拼接

Question

I have two array. I want to delete these elements of array after equal according to other array length. it removes elements. but it removes all elements of both arrays. why is it remove all elements of both arrays?

var fruits = ["Banana", "Orange", "Apple", "Mango"];
let sefa = [];
document.getElementById("demo").innerHTML = fruits;

function myFunction() {

sefa = fruits;
fruits.push("element-1");
fruits.push("element-2");

  fruits.splice(0, sefa.length);
  document.getElementById("demo").innerHTML = fruits;
}

console.log(fruits) => Array[]

Answer 1

It removes all the elements of both the arrays because when you do sefa=fruits. It gives the address of fruits array to the array sefa.

I think instead you should do

sefa = fruits.slice(0,fruits.length);

By this if you remove all the elements of fruits till the length of sefa. The sefa array still remains untouched, because the slice function makes a copy of fruits array and gives it to sefa instead of giving the address.