Name: rx.priorityqueue
Owner: Reactive Extensions
Description: Standalone Priority Queue from the RxJS library
Created: 2016-01-05 22:19:09.0
Updated: 2018-04-20 14:36:38.0
Pushed: 2016-01-07 19:42:54.0
Homepage: null
Size: 12
Language: JavaScript
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rx.priorityqueue - Standalone PriorityQueue from the RxJS libraryThis is a standalone version of the RxJS PriorityQueue class. This class allows you to keep items in priority order based upon standard ordering or a custom ordering function that you provide. In RxJS, this is used heavily in the schedulers to ensure that all operations are executed in the precise order.
The rx.priorityqueue library can be installed by the following:
m install rx.priorityqueue
You can use the PriorityQueue to keep items in order such as the following:
t q = new PriorityQueue();
queue(42);
queue(41);
queue(44);
queue(43);
ole.log(`queue length is ${q.length}`);
> queue length is 4
ole.log(`dequeued value is ${q.dequeue()}`);
> First value is 41
ole.log(`dequeued value is ${q.dequeue()}`);
> dequeued value is 42
ole.log(`dequeued value is ${q.dequeue()}`);
> dequeued value is 43
ole.log(`dequeued value is ${q.dequeue()}`);
> dequeued value is 44
You can also use your own custom comparer for complex objects to determine order. To do that, simply pass in a function which takes two arguments, the left hand side and right hand side. By default, the comparer function which is used looks like the following where if the left is greater than it should be positive, less than, should be negative and equal should be zero. Else, if you want to have it on the object compared directly, simply implement compareTo on the object to be compared and then it will work.
tion defaultComparer (x, y) {
(x > y) {
return 1;
else if (y > x) {
return -1;
else {
return 0;
Knowing this, we can now apply this to our custom object:
tion createItem(dueTime, action) {
turn {
dueTime,
action
tion comparer (x, y) { return x.dueTime - y.dueTime; }
q = new PriorityQueue(comparer);
queue(createItem(new Date(42), () => console.log(42)));
queue(createItem(new Date(41), () => console.log(41)));
queue(createItem(new Date(44), () => console.log(44)));
queue(createItem(new Date(43), () => console.log(43)));
queue().action();
> 41
queue().action();
> 42
queue().action();
> 43
queue().action();
> 44
PriorityQueue constructorPriorityQueue Instance MethodsPriorityQueue Instance PropertiesPriorityQueue(comparer)Creates a queue organized by priority based upon the comparer to determine order.
[comparer]: Function - The comparer used to determine order. If not specified this will default to determining order using greater than, less than.tion createItem(dueTime, action) {
turn {
dueTime,
action
tion comparer (x, y) { return x.dueTime - y.dueTime; }
q = new PriorityQueue(comparer);
queue(createItem(new Date(42), () => console.log(42)));
PriorityQueue.prototype.dequeue()Removes the first item from the queue and returns the value.
Any - The first item in the priority queue.
t q = new PriorityQueue();
queue(42);
ole.log(q.dequeue());
> 42
ole.log(q.length);
> 0
PriorityQueue.prototype.enqueue(item)Adds an item to the priority queue which is then reordered based upon priority.
item: Any - The item to add to the priority queue.t q = new PriorityQueue();
queue(42);
ole.log(q.length);
> 1
PriorityQueue.prototype.peek()Returns the first item in the priority queue.
Any - The first item in the priority queue.
t q = new PriorityQueue();
queue(42);
ole.log(q.peek());
> 42
ole.log(q.length);
> 1
PriorityQueue.prototype.remove(item)Removes the specified item from the priority queue.
item: Any - The item to remove from the priority queue.Boolean - true if removed; else false.
t q = new PriorityQueue();
queue(42);
ole.log(`Item was removed is ${q.dequeue()}`);
> Item was remove is true
lengthGets the length of the priority queue
t q = new PriorityQueue();
queue(42);
ole.log(`Priority queue length is ${q.length}`);
> Priority queue length is 1
We appreciate any contributions by the community as long as they abide by the Code of Conduct.
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Documentation
Code
The MIT License (MIT)
Copyright (c) 2016 Microsoft Corporation
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.