javascript - I push a value to an array in foreach, why does this result appear?

Question

let arr = []
arr.push(1)
let arr2 = [2,3,4,5]
arr2.forEach((item,index,arr)=>{
    arr.push(item)
  console.log(arr)
})

The result is

[2, 3, 4, 5, 2]
[2, 3, 4, 5, 2, 3]
[2, 3, 4, 5, 2, 3, 4]
[2, 3, 4, 5, 2, 3, 4, 5]

jsbin address
https://jsbin.com/papamadejo/...
I want to know why this is the result
It shouldn’t be [1,2,3,4,5] What

Answer 1

The arr variable in foreach has the same name, so arr2 is operated.
Delete the third parameter (arr)

Answer 2

That’s it, you can refer to the instructions on Yiha mdn:

in this code

arr2.forEach((item,index,arr)=>{
    arr.push(item)
  console.log(arr)
})

arr points to arr2.

You can make the following modifications

let arr1 = []
arr.push(1)
let arr2 = [2,3,4,5]
arr2.forEach((item,index)=>{
    arr1.push(item)
  console.log(arr1)
})