| 7 | } |
| 8 | |
| 9 | class DoubleLinkedList { |
| 10 | constructor() { |
| 11 | this.length = 0 |
| 12 | this.head = null |
| 13 | this.tail = null |
| 14 | } |
| 15 | |
| 16 | // Add new element |
| 17 | append(element) { |
| 18 | const node = new Node(element) |
| 19 | |
| 20 | if (!this.head) { |
| 21 | this.head = node |
| 22 | this.tail = node |
| 23 | } else { |
| 24 | node.prev = this.tail |
| 25 | this.tail.next = node |
| 26 | this.tail = node |
| 27 | } |
| 28 | |
| 29 | this.length++ |
| 30 | } |
| 31 | |
| 32 | // Add element |
| 33 | insert(position, element) { |
| 34 | // Check of out-of-bound values |
| 35 | if (position >= 0 && position <= this.length) { |
| 36 | const node = new Node(element) |
| 37 | let current = this.head |
| 38 | let previous = 0 |
| 39 | let index = 0 |
| 40 | |
| 41 | if (position === 0) { |
| 42 | if (!this.head) { |
| 43 | this.head = node |
| 44 | this.tail = node |
| 45 | } else { |
| 46 | node.next = current |
| 47 | current.prev = node |
| 48 | this.head = node |
| 49 | } |
| 50 | } else if (position === this.length) { |
| 51 | current = this.tail |
| 52 | current.next = node |
| 53 | node.prev = current |
| 54 | this.tail = node |
| 55 | } else { |
| 56 | while (index++ < position) { |
| 57 | previous = current |
| 58 | current = current.next |
| 59 | } |
| 60 | |
| 61 | node.next = current |
| 62 | previous.next = node |
| 63 | |
| 64 | // New |
| 65 | current.prev = node |
| 66 | node.prev = previous |
nothing calls this directly
no outgoing calls
no test coverage detected