Maybe there are some redundent code in Doubly-Linked-List

    reverse() {
        let node = this.head,
            previous = null,
            next = null;

        while (node) {
            next = node.next;
            console.log(previous?.value);
            previous = node.previous;
            console.log(previous?.value);
            node.next = previous;            
            node.previous = next;

            previous = node;
            node = next;
        }
        this.tail = this.head;
        this.head = previous;
        return this;
    }

I think the code previous = node.previous; in while loop is redundent code. I try this code and the previous.vaule always get a same value.

Start with the Doubly-Linked-List reverse() implementation shown in the issue and trace the previous, node, and next assignments through the loop. Determine whether the questioned assignment changes the result or is redundant, then confirm that the reversal behavior remains correct after any change.