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Linked lists in Javascript
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/** | |
* Linked lists in Javascript | |
* @see https://dev.to/ryanfarney3/intro-to-linked-lists-in-js-19b4 | |
*/ | |
class Node { | |
constructor(data, next = null) { | |
this.data = data; | |
this.next = next; | |
} | |
} | |
class LinkedList { | |
constructor(data = null) { | |
this.head = data; | |
} | |
first() { | |
return this.head; | |
} | |
last() { | |
let node = this.head; | |
if (!node) return null; | |
while (node) { | |
if (node.next === null) return node; | |
node = node.next; | |
} | |
} | |
prepend(data) { | |
this.head = new Node(data, this.head); | |
} | |
reset() { | |
this.head = null; | |
} | |
removeFirst() { | |
if (!this.head) return; | |
this.head = this.head.next; | |
} | |
removeLast() { | |
if (!this.head) return; | |
if (!this.head.next) return this.head = null; | |
let prev = this.head; | |
while (prev) { | |
let node = prev.next; | |
if (!node.next) return prev.next = null; | |
prev = prev.next; | |
} | |
} | |
push(data) { | |
const node = new Node(data); | |
const last = this.last(); | |
if (last) { | |
last.next = node; | |
} else { | |
this.head = node; | |
} | |
} | |
count() { | |
let counter = 0; | |
let node = this.head; | |
while (node) { | |
counter++; | |
node = node.next; | |
} | |
return counter; | |
} | |
isEmpty() { | |
return this.count() === 0; | |
} | |
} |
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