'use strict' module.exports = Yallist Yallist.Node = Node Yallist.create = Yallist function Yallist (list) { var self = this if (!(self instanceof Yallist)) { self = new Yallist() } self.tail = null self.head = null self.length = 0 if (list && typeof list.forEach === 'function') { list.forEach(function (item) { self.push(item) }) } else if (arguments.length > 0) { for (var i = 0, l = arguments.length; i < l; i++) { self.push(arguments[i]) } } return self } Yallist.prototype.removeNode = function (node) { if (node.list !== this) { throw new Error('removing node which does not belong to this list') } var next = node.next var prev = node.prev if (next) { next.prev = prev } if (prev) { prev.next = next } if (node === this.head) { this.head = next } if (node === this.tail) { this.tail = prev } node.list.length-- node.next = null node.prev = null node.list = null return next } Yallist.prototype.unshiftNode = function (node) { if (node === this.head) { return } if (node.list) { node.list.removeNode(node) } var head = this.head node.list = this node.next = head if (head) { head.prev = node } this.head = node if (!this.tail) { this.tail = node } this.length++ } Yallist.prototype.pushNode = function (node) { if (node === this.tail) { return } if (node.list) { node.list.removeNode(node) } var tail = this.tail node.list = this node.prev = tail if (tail) { tail.next = node } this.tail = node if (!this.head) { this.head = node } this.length++ } Yallist.prototype.push = function () { for (var i = 0, l = arguments.length; i < l; i++) { push(this, arguments[i]) } return this.length } Yallist.prototype.unshift = function () { for (var i = 0, l = arguments.length; i < l; i++) { unshift(this, arguments[i]) } return this.length } Yallist.prototype.pop = function () { if (!this.tail) { return undefined } var res = this.tail.value this.tail = this.tail.prev if (this.tail) { this.tail.next = null } else { this.head = null } this.length-- return res } Yallist.prototype.shift = function () { if (!this.head) { return undefined } var res = this.head.value this.head = this.head.next if (this.head) { this.head.prev = null } else { this.tail = null } this.length-- return res } Yallist.prototype.forEach = function (fn, thisp) { thisp = thisp || this for (var walker = this.head, i = 0; walker !== null; i++) { fn.call(thisp, walker.value, i, this) walker = walker.next } } Yallist.prototype.forEachReverse = function (fn, thisp) { thisp = thisp || this for (var walker = this.tail, i = this.length - 1; walker !== null; i--) { fn.call(thisp, walker.value, i, this) walker = walker.prev } } Yallist.prototype.get = function (n) { for (var i = 0, walker = this.head; walker !== null && i < n; i++) { // abort out of the list early if we hit a cycle walker = walker.next } if (i === n && walker !== null) { return walker.value } } Yallist.prototype.getReverse = function (n) { for (var i = 0, walker = this.tail; walker !== null && i < n; i++) { // abort out of the list early if we hit a cycle walker = walker.prev } if (i === n && walker !== null) { return walker.value } } Yallist.prototype.map = function (fn, thisp) { thisp = thisp || this var res = new Yallist() for (var walker = this.head; walker !== null;) { res.push(fn.call(thisp, walker.value, this)) walker = walker.next } return res } Yallist.prototype.mapReverse = function (fn, thisp) { thisp = thisp || this var res = new Yallist() for (var walker = this.tail; walker !== null;) { res.push(fn.call(thisp, walker.value, this)) walker = walker.prev } return res } Yallist.prototype.reduce = function (fn, initial) { var acc var walker = this.head if (arguments.length > 1) { acc = initial } else if (this.head) { walker = this.head.next acc = this.head.value } else { throw new TypeError('Reduce of empty list with no initial value') } for (var i = 0; walker !== null; i++) { acc = fn(acc, walker.value, i) walker = walker.next } return acc } Yallist.prototype.reduceReverse = function (fn, initial) { var acc var walker = this.tail if (arguments.length > 1) { acc = initial } else if (this.tail) { walker = this.tail.prev acc = this.tail.value } else { throw new TypeError('Reduce of empty list with no initial value') } for (var i = this.length - 1; walker !== null; i--) { acc = fn(acc, walker.value, i) walker = walker.prev } return acc } Yallist.prototype.toArray = function () { var arr = new Array(this.length) for (var i = 0, walker = this.head; walker !== null; i++) { arr[i] = walker.value walker = walker.next } return arr } Yallist.prototype.toArrayReverse = function () { var arr = new Array(this.length) for (var i = 0, walker = this.tail; walker !== null; i++) { arr[i] = walker.value walker = walker.prev } return arr } Yallist.prototype.slice = function (from, to) { to = to || this.length if (to < 0) { to += this.length } from = from || 0 if (from < 0) { from += this.length } var ret = new Yallist() if (to < from || to < 0) { return ret } if (from < 0) { from = 0 } if (to > this.length) { to = this.length } for (var i = 0, walker = this.head; walker !== null && i < from; i++) { walker = walker.next } for (; walker !== null && i < to; i++, walker = walker.next) { ret.push(walker.value) } return ret } Yallist.prototype.sliceReverse = function (from, to) { to = to || this.length if (to < 0) { to += this.length } from = from || 0 if (from < 0) { from += this.length } var ret = new Yallist() if (to < from || to < 0) { return ret } if (from < 0) { from = 0 } if (to > this.length) { to = this.length } for (var i = this.length, walker = this.tail; walker !== null && i > to; i--) { walker = walker.prev } for (; walker !== null && i > from; i--, walker = walker.prev) { ret.push(walker.value) } return ret } Yallist.prototype.splice = function (start, deleteCount, ...nodes) { if (start > this.length) { start = this.length - 1 } if (start < 0) { start = this.length + start; } for (var i = 0, walker = this.head; walker !== null && i < start; i++) { walker = walker.next } var ret = [] for (var i = 0; walker && i < deleteCount; i++) { ret.push(walker.value) walker = this.removeNode(walker) } if (walker === null) { walker = this.tail } if (walker !== this.head && walker !== this.tail) { walker = walker.prev } for (var i = 0; i < nodes.length; i++) { walker = insert(this, walker, nodes[i]) } return ret; } Yallist.prototype.reverse = function () { var head = this.head var tail = this.tail for (var walker = head; walker !== null; walker = walker.prev) { var p = walker.prev walker.prev = walker.next walker.next = p } this.head = tail this.tail = head return this } function insert (self, node, value) { var inserted = node === self.head ? new Node(value, null, node, self) : new Node(value, node, node.next, self) if (inserted.next === null) { self.tail = inserted } if (inserted.prev === null) { self.head = inserted } self.length++ return inserted } function push (self, item) { self.tail = new Node(item, self.tail, null, self) if (!self.head) { self.head = self.tail } self.length++ } function unshift (self, item) { self.head = new Node(item, null, self.head, self) if (!self.tail) { self.tail = self.head } self.length++ } function Node (value, prev, next, list) { if (!(this instanceof Node)) { return new Node(value, prev, next, list) } this.list = list this.value = value if (prev) { prev.next = this this.prev = prev } else { this.prev = null } if (next) { next.prev = this this.next = next } else { this.next = null } } try { // add if support for Symbol.iterator is present require('./iterator.js')(Yallist) } catch (er) {}