LinkedList

class LinkedList {
    constructor(...values) {
        this.head = null;
        this.length = 0;
        this.addToHead(...values);
    }
    
    _addSingleItemToHead(value) {
      const newNode = { value };
      newNode.next = this.head;
      this.head = newNode;
      this.length++;
    }
    
    addToHead(...values) {
        values.forEach(value => this._addSingleItemToHead(value));
        return this;
    }
    
    removeFromHead() {
        if (this.length === 0) {
            return undefined;
        }
        
        const value = this.head.value;
        this.head = this.head.next;
        this.length--;
        
        return value;
    }
    
    find(val) {
        let thisNode = this.head;
        
        while(thisNode) {
            if(thisNode.value === val) {
                return thisNode;
            }
            
            thisNode = thisNode.next;
        }
        
        return thisNode;
    }
    
    remove(val) {
        if(this.length === 0) {
            return undefined;
        }
        
        if (this.head.value === val) {
            return this.removeFromHead();
        }
        
        let previousNode = this.head;
        let thisNode = previousNode.next;
        
        while(thisNode) {
            if(thisNode.value === val) {
                break;
            }
            
            previousNode = thisNode;
            thisNode = thisNode.next;
        }
        
        if (thisNode === null) {
            return undefined;
        }
        
        previousNode.next = thisNode.next;
        this.length--;
        return this;
    }
}