So I have homework that requires me to dequeue from an array like so:

let arr = [1, 2, 3]

My only problem is that I'm restricted in using any array method except for the .length method.

I have tried using the delete to remove the first element but I know it doesn't adjust the array and reflects undefined for the first element:

function dequeue(){
  delete arr[0];
  console.log(arr)
}

Any help or advice on how to do it is highly appreciated.

CodePudding user response：

Assuming, you can still use assigment with index, you could copy all items one index before and decrement the length of the array.

let array = [1, 2, 3];

for (let i = 1; i < array.length; i  ) array[i - 1] = array[i];

array.length--;

console.log(array);

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CodePudding user response：

If .map is allowed to use in your case.

array = array.map((elm,index,arr) => arr[index 1]);
array.length--;

CodePudding user response：

You can use Destructuring assignment. try this out:

const [firstElement, ...restOfTheArray] = yourArray;

restOfTheArray is the same array with the first element removed.