Package Exports
- fast-list
This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (fast-list) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.
Readme
The Problem
You've got some thing where you need to push a bunch of stuff into a queue and then shift it out. Or, maybe it's a stack, and you're just pushing and popping it.
Arrays work for this, but are a bit costly performance-wise.
The Solution
A linked-list implementation that takes advantage of what v8 is good at: creating objects with a known shape.
This is faster for this use case. How much faster? About 50%.
$ node bench.js
benchmarking /Users/isaacs/dev-src/js/fast-list/bench.js
Please be patient.
{ node: '0.6.2-pre',
v8: '3.6.6.8',
ares: '1.7.5-DEV',
uv: '0.1',
openssl: '0.9.8l' }
Scores: (bigger is better)
new FastList()
Raw:
> 22556.39097744361
> 23054.755043227666
> 22770.398481973436
> 23414.634146341465
> 23099.133782483157
Average (mean) 22979.062486293868
[]
Raw:
> 12195.121951219513
> 12184.508268059182
> 12173.91304347826
> 12216.404886561955
> 12184.508268059182
Average (mean) 12190.891283475617
new Array()
Raw:
> 12131.715771230503
> 12184.508268059182
> 12216.404886561955
> 12195.121951219513
> 11940.298507462687
Average (mean) 12133.609876906768
Winner: new FastList()
Compared with next highest ([]), it's:
46.95% faster
1.88 times as fast
0.28 order(s) of magnitude faster
Compared with the slowest (new Array()), it's:
47.2% faster
1.89 times as fast
0.28 order(s) of magnitude faster
This lacks a lot of features that arrays have:
- You can't specify the size at the outset.
- It's not indexable.
- There's no join, concat, etc.
If any of this matters for your use case, you're probably better off using an Array object.
Installing
npm install fast-list
API
var FastList = require("fast-list")
var list = new FastList()
list.push("foo")
list.unshift("bar")
list.push("baz")
console.log(list.length) // 2
console.log(list.pop()) // baz
console.log(list.shift()) // bar
console.log(list.shift()) // foo
Methods
push
: Just like Array.push, but only can take a single entrypop
: Just like Array.popshift
: Just like Array.shiftunshift
: Just like Array.unshift, but only can take a single entrydrop
: Drop all entriesitem(n)
: Retrieve the nth item in the list. This involves a walk every time. It's very slow. If you find yourself using this, consider using a normal Array instead.slice(start, end)
: Retrieve an array of the items at this position. This involves a walk every time. It's very slow. If you find yourself using this, consider using a normal Array instead.
Members
length
: The number of things in the list. Note that, unlike Array.length, this is not a getter/setter, but rather a counter that is internally managed. Setting it can only cause harm.