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diff --git a/node_modules/regex-cache/README.md b/node_modules/regex-cache/README.md new file mode 100644 index 000000000..ab19174fb --- /dev/null +++ b/node_modules/regex-cache/README.md @@ -0,0 +1,160 @@ +# regex-cache [](https://www.npmjs.com/package/regex-cache) [](https://npmjs.org/package/regex-cache) [](https://travis-ci.org/jonschlinkert/regex-cache) + +> Memoize the results of a call to the RegExp constructor, avoiding repetitious runtime compilation of the same string and options, resulting in suprising performance improvements. + +## Install + +Install with [npm](https://www.npmjs.com/): + +```sh +$ npm install regex-cache --save +``` + +* Read [what this does](#what-this-does). +* See [the benchmarks](#benchmarks) + +## Usage + +Wrap a function like this: + +```js +var cache = require('regex-cache'); +var someRegex = cache(require('some-regex-lib')); +``` + +**Caching a regex** + +If you want to cache a regex after calling `new RegExp()`, or you're requiring a module that returns a regex, wrap it with a function first: + +```js +var cache = require('regex-cache'); + +function yourRegex(str, opts) { + // do stuff to str and opts + return new RegExp(str, opts.flags); +} + +var regex = cache(yourRegex); +``` + +## Recommendations + +### Use this when... + +* **No options are passed** to the function that creates the regex. Regardless of how big or small the regex is, when zero options are passed, caching will be faster than not. +* **A few options are passed**, and the values are primitives. The limited benchmarks I did show that caching is beneficial when up to 8 or 9 options are passed. + +### Do not use this when... + +* **The values of options are not primitives**. When non-primitives must be compared for equality, the time to compare the options is most likely as long or longer than the time to just create a new regex. + +### Example benchmarks + +Performance results, with and without regex-cache: + +```bash +# no args passed (defaults) + with-cache x 8,699,231 ops/sec ±0.86% (93 runs sampled) + without-cache x 2,777,551 ops/sec ±0.63% (95 runs sampled) + +# string and six options passed + with-cache x 1,885,934 ops/sec ±0.80% (93 runs sampled) + without-cache x 1,256,893 ops/sec ±0.65% (97 runs sampled) + +# string only + with-cache x 7,723,256 ops/sec ±0.87% (92 runs sampled) + without-cache x 2,303,060 ops/sec ±0.47% (99 runs sampled) + +# one option passed + with-cache x 4,179,877 ops/sec ±0.53% (100 runs sampled) + without-cache x 2,198,422 ops/sec ±0.47% (95 runs sampled) + +# two options passed + with-cache x 3,256,222 ops/sec ±0.51% (99 runs sampled) + without-cache x 2,121,401 ops/sec ±0.79% (97 runs sampled) + +# six options passed + with-cache x 1,816,018 ops/sec ±1.08% (96 runs sampled) + without-cache x 1,157,176 ops/sec ±0.53% (100 runs sampled) + +# +# diminishing returns happen about here +# + +# ten options passed + with-cache x 1,210,598 ops/sec ±0.56% (92 runs sampled) + without-cache x 1,665,588 ops/sec ±1.07% (100 runs sampled) + +# twelve options passed + with-cache x 1,042,096 ops/sec ±0.68% (92 runs sampled) + without-cache x 1,389,414 ops/sec ±0.68% (97 runs sampled) + +# twenty options passed + with-cache x 661,125 ops/sec ±0.80% (93 runs sampled) + without-cache x 1,208,757 ops/sec ±0.65% (97 runs sampled) + +# +# when non-primitive values are compared +# + +# single value on the options is an object + with-cache x 1,398,313 ops/sec ±1.05% (95 runs sampled) + without-cache x 2,228,281 ops/sec ±0.56% (99 runs sampled) +``` + +## Run benchmarks + +Install dev dependencies: + +```bash +npm i -d && npm run benchmarks +``` + +## What this does + +If you're using `new RegExp('foo')` instead of a regex literal, it's probably because you need to dyamically generate a regex based on user options or some other potentially changing factors. + +When your function creates a string based on user inputs and passes it to the `RegExp` constructor, regex-cache caches the results. The next time the function is called if the key of a cached regex matches the user input (or no input was given), the cached regex is returned, avoiding unnecessary runtime compilation. + +Using the RegExp constructor offers a lot of flexibility, but the runtime compilation comes at a price - it's slow. Not specifically because of the call to the RegExp constructor, but **because you have to build up the string before `new RegExp()` is even called**. +## Contributing + +Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](https://github.com/jonschlinkert/regex-cache/issues/new). + +## Building docs + +Generate readme and API documentation with [verb](https://github.com/verbose/verb): + +```sh +$ npm install verb && npm run docs +``` + +Or, if [verb](https://github.com/verbose/verb) is installed globally: + +```sh +$ verb +``` + +## Running tests + +Install dev dependencies: + +```sh +$ npm install -d && npm test +``` + +## Author + +**Jon Schlinkert** + +* [github/jonschlinkert](https://github.com/jonschlinkert) +* [twitter/jonschlinkert](http://twitter.com/jonschlinkert) + +## License + +Copyright © 2016, [Jon Schlinkert](https://github.com/jonschlinkert). +Released under the [MIT license](https://github.com/jonschlinkert/regex-cache/blob/master/LICENSE). + +*** + +_This file was generated by [verb](https://github.com/verbose/verb), v, on April 01, 2016._
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