OSet

Ordered Set Data Structure

About

OSet is a very small JavaScript library, providing an ordered set data structure, i.e., a data structure providing set functionality where the insertion order of the items is preserved. This type of data structure is important if a collection of items should be hold and it is important to be able to interate over the items in a particular order, too.

Installation

Node environments (with NPM package manager):

$ npm install oset

Browser environments (with Bower package manager):

$ bower install oset

Usage

Main Operations

• new OSet(): OSet: [O(1)]
  Create a new empty set instance.

• OSet#length(): Number: [O(1)]
  Get number of items in the set.

• OSet#has(key: String): Boolean: [O(1)]
  Check whether item exists under key.

• OSet#get(key: String): Object: [O(1)]
  Get value of item under key. If no object exists under key the value undefined is returned.

• OSet#set(key: String, val: Object): OSet: [O(1)]
  Set value of item under key. If there is already an item stored under key, replace its value. Else insert as a new item into the set.

• OSet#del(key: String): OSet: [O(1)]
  Delete item under key. If no object exists under key an exception is thrown.

Convenience Operations

• OSet#clear(): OSet: [O(n)]
  Delete all items under key.

• OSet#keys(): String[]: [O(n)]
  Get the list of keys of all items in the set, in insertion order.

• OSet#values(): Object[]: [O(n)]
  Get the list of values of all items in the set, in insertion order.

• OSet#find(predicate: (val: Object, key: String, order: Number) => Boolean, ctx: Object): Object[]: [O(n)]
  Iterate over all items in the set, in insertion order, and call the predicate function for each object. The function receives the item value, the item key and the iteration order (starting from zero and steadily increasing). If predicate returns true the item is placed into the result array of items.

• OSet#each(iterator: (val: Object, key: String, order: Number) => Void, ctx: Object): Object: [O(n)]
  Iterate over all items in the set, in insertion order, and call the iterator function for each object. The function receives the item value, the item key and the iteration order (starting from zero and steadily increasing). The function returns the passed ctx object.

• OSet#merge(other: OSet): OSet: [O(n)]
  Merge all items of other into the set. The merged items are removed from other.

• OSet#union(other: OSet): OSet: [O(n)]
  Return a new set created through the union of the target set and the other set. Both the target and the other set are not modified.

• OSet#intersection(other: OSet): OSet: [O(n)]
  Return a new set created through the intersection of the target set and the other set. Both the target and the other set are not modified.

• OSet#difference(other: OSet): OSet: [O(n)]
  Return a new set created through the difference/complement of the target set and the other set. Both the target and the other set are not modified.

Implementation Notice

Although OSet is written in ECMAScript 6, it is transpiled to ECMAScript 5 and this way runs in really all(!) current (as of 2015) JavaScript environments, of course.

Internally, OSet is based on a managing all objects in a ring of double-linked buckets. This way it can achieve the O(1) time complexity in all its main operations.

License

Copyright (c) 2015 Ralf S. Engelschall (http://engelschall.com/)

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.