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unboundedpress/node_modules/async/internal/DoublyLinkedList.js

92 lines
2.2 KiB
JavaScript

5 years ago
"use strict";
Object.defineProperty(exports, "__esModule", {
value: true
});
// Simple doubly linked list (https://en.wikipedia.org/wiki/Doubly_linked_list) implementation
// used for queues. This implementation assumes that the node provided by the user can be modified
// to adjust the next and last properties. We implement only the minimal functionality
// for queue support.
class DLL {
constructor() {
this.head = this.tail = null;
this.length = 0;
}
removeLink(node) {
if (node.prev) node.prev.next = node.next;else this.head = node.next;
if (node.next) node.next.prev = node.prev;else this.tail = node.prev;
node.prev = node.next = null;
this.length -= 1;
return node;
}
empty() {
while (this.head) this.shift();
return this;
}
insertAfter(node, newNode) {
newNode.prev = node;
newNode.next = node.next;
if (node.next) node.next.prev = newNode;else this.tail = newNode;
node.next = newNode;
this.length += 1;
}
insertBefore(node, newNode) {
newNode.prev = node.prev;
newNode.next = node;
if (node.prev) node.prev.next = newNode;else this.head = newNode;
node.prev = newNode;
this.length += 1;
}
unshift(node) {
if (this.head) this.insertBefore(this.head, node);else setInitial(this, node);
}
push(node) {
if (this.tail) this.insertAfter(this.tail, node);else setInitial(this, node);
}
shift() {
return this.head && this.removeLink(this.head);
}
pop() {
return this.tail && this.removeLink(this.tail);
}
toArray() {
return [...this];
}
*[Symbol.iterator]() {
var cur = this.head;
while (cur) {
yield cur.data;
cur = cur.next;
}
}
remove(testFn) {
var curr = this.head;
while (curr) {
var { next } = curr;
if (testFn(curr)) {
this.removeLink(curr);
}
curr = next;
}
return this;
}
}
exports.default = DLL;
function setInitial(dll, node) {
dll.length = 1;
dll.head = dll.tail = node;
}
module.exports = exports["default"];