ordered-set is a performant ES6 Set subclass that allows control
over iteration order.
Simply provide the set with the ordering function to use and it will
do the rest.
const OrderedSet = require('ordered-set')
let orderedSet = new OrderedSet()
orderedSet.use(mySortingFunction)
orderedSet.add(item)
orderedSet.add(item2)
for (let setItem of orderedSet) {
// iterates in order defined by mySortingFunction
}npm install ordered-set
const OrderedSet = require('ordered-set')
// Default sortFunction is numeric, ascending:
// (a, b) => a - b
let orderedSet = new OrderedSet()
orderedSet.add(2)
orderedSet.add(1)
orderedSet.add(3)
orderedSet.forEach(item => console.log('orderedSet default sortFunction', item))
// orderedSet default sortFunction 1
// orderedSet default sortFunction 2
// orderedSet default sortFunction 3orderedSet.use((a, b) => b - a) // e.g. reversed ordering
orderedSet.forEach(item => console.log('orderedSet custom sortFunction', item))
// orderedSet custom sortFunction 3
// orderedSet custom sortFunction 2
// orderedSet custom sortFunction 1let regularSet = new Set()
regularSet.add(2)
regularSet.add(1)
regularSet.add(3)regularSet.forEach(item => console.log('regular set', item))
// regular set 2
// regular set 1
// regular set 3orderedSet = new OrderedSet([3,2,1])
orderedSet.add(0)
console.log('orderedSet.size', orderedSet.size) // set.size 4
orderedSet.delete(0)
console.log('orderedSet.size', orderedSet.size) // set.size 3Although the code is compiled and published as ES5, there are some ES6 standard library features required:
- Symbols
- Set
Install 6to5 or use core-js directly. traceur also works well. Unfortunately, did not have luck using the more lightweight & modular es6-set & es6-symbol.
You'll need to install an ES6 polyfill yourself, such as those listed above. There is not one included with the package on purpose – this may seem like malpractice and I normally would advise against any kind of implicit dependencies but after battling with these issues across multiple projects I've concluded npm currently has no suitable workflow for anything that must be a singleton/mutates the global environment. You're better off just adding the dependency manually to your parent package.
I feel this should be best-practice for language polyfills – by omitting a transpiler you're free to use this with whatever transpiler you're already using.
This lib could be easily reworked to not require these ES6 features but the intended audience is people already compiling to ES6, or those interested in doing so.
MIT