当数组存储为全局变量时，增加数组索引不起作用

Question

I'm trying to update array index as function incIndex runs:

const arr=[1, 2, 3, 4, 5];
let index = 0;
let arrIndex = arr[index]
const incIndex = () => index++;

but it only works this way

console.log(arr[index]) // 1
incIndex();
console.log(arr[index]) // 2

but when I do

console.log(arrIndex) // 1
incIndex();
console.log(arrIndex) // 1

I still get element of index 0. Does anyone know how to fix it so I can use 2nd way?

Answer 1

you can do it using a for loop

const arr=[1, 2, 3, 4, 5];

for(let i = 0; i < arr.length; i++)
{
  console.log(arr[i]);
}

where the i variable in the loop would be the increasing index

Answer 2

You are doing it wrong.

This one copies the value of the first element of the array to a new variable.

let arrIndex = arr[index]

You can't expect it to be changed when changing the index.

Answer 3

arrIndex value will be always the same if you don't replace the value after the first declaration. (Also you are missing a semicolon at the end)

If you set arrIndex = arr[index] , it will be equal to the value of arr[index] at the moment you assign it (1). It is not a dynamic value.

For a dynamic value you maybe can create a function but it doesn't worth it. It's better to use arr[index]

function returnDynamicValue(){
    return arr[index];
}

And then

console.log(returnDynamicValue());
incIndex();
console.log(returnDynamicValue());