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author | 2020-11-18 23:26:45 +0100 | |
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committer | 2020-11-18 23:26:45 +0100 | |
commit | 81ddf9b700bc48a1f8e472209f080f9c1d9a9b09 (patch) | |
tree | 8b959d50c5a614cbf9fcb346ed556140374d4b6d /node_modules/reusify/README.md | |
parent | 1870f3fdf43707a15fda0f609a021f516f45eb63 (diff) | |
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diff --git a/node_modules/reusify/README.md b/node_modules/reusify/README.md deleted file mode 100644 index badcb7c..0000000 --- a/node_modules/reusify/README.md +++ /dev/null @@ -1,145 +0,0 @@ -# reusify - -[![npm version][npm-badge]][npm-url] -[![Build Status][travis-badge]][travis-url] -[![Coverage Status][coveralls-badge]][coveralls-url] - -Reuse your objects and functions for maximum speed. This technique will -make any function run ~10% faster. You call your functions a -lot, and it adds up quickly in hot code paths. - -``` -$ node benchmarks/createNoCodeFunction.js -Total time 53133 -Total iterations 100000000 -Iteration/s 1882069.5236482036 - -$ node benchmarks/reuseNoCodeFunction.js -Total time 50617 -Total iterations 100000000 -Iteration/s 1975620.838848608 -``` - -The above benchmark uses fibonacci to simulate a real high-cpu load. -The actual numbers might differ for your use case, but the difference -should not. - -The benchmark was taken using Node v6.10.0. - -This library was extracted from -[fastparallel](http://npm.im/fastparallel). - -## Example - -```js -var reusify = require('reusify') -var fib = require('reusify/benchmarks/fib') -var instance = reusify(MyObject) - -// get an object from the cache, -// or creates a new one when cache is empty -var obj = instance.get() - -// set the state -obj.num = 100 -obj.func() - -// reset the state. -// if the state contains any external object -// do not use delete operator (it is slow) -// prefer set them to null -obj.num = 0 - -// store an object in the cache -instance.release(obj) - -function MyObject () { - // you need to define this property - // so V8 can compile MyObject into an - // hidden class - this.next = null - this.num = 0 - - var that = this - - // this function is never reallocated, - // so it can be optimized by V8 - this.func = function () { - if (null) { - // do nothing - } else { - // calculates fibonacci - fib(that.num) - } - } -} -``` - -The above example was intended for synchronous code, let's see async: -```js -var reusify = require('reusify') -var instance = reusify(MyObject) - -for (var i = 0; i < 100; i++) { - getData(i, console.log) -} - -function getData (value, cb) { - var obj = instance.get() - - obj.value = value - obj.cb = cb - obj.run() -} - -function MyObject () { - this.next = null - this.value = null - - var that = this - - this.run = function () { - asyncOperation(that.value, that.handle) - } - - this.handle = function (err, result) { - that.cb(err, result) - that.value = null - that.cb = null - instance.release(that) - } -} -``` - -Also note how in the above examples, the code, that consumes an istance of `MyObject`, -reset the state to initial condition, just before storing it in the cache. -That's needed so that every subsequent request for an instance from the cache, -could get a clean instance. - -## Why - -It is faster because V8 doesn't have to collect all the functions you -create. On a short-lived benchmark, it is as fast as creating the -nested function, but on a longer time frame it creates less -pressure on the garbage collector. - -## Other examples -If you want to see some complex example, checkout [middie](https://github.com/fastify/middie) and [steed](https://github.com/mcollina/steed). - -## Acknowledgements - -Thanks to [Trevor Norris](https://github.com/trevnorris) for -getting me down the rabbit hole of performance, and thanks to [Mathias -Buss](http://github.com/mafintosh) for suggesting me to share this -trick. - -## License - -MIT - -[npm-badge]: https://badge.fury.io/js/reusify.svg -[npm-url]: https://badge.fury.io/js/reusify -[travis-badge]: https://api.travis-ci.org/mcollina/reusify.svg -[travis-url]: https://travis-ci.org/mcollina/reusify -[coveralls-badge]: https://coveralls.io/repos/mcollina/reusify/badge.svg?branch=master&service=github -[coveralls-url]: https://coveralls.io/github/mcollina/reusify?branch=master |