Package Exports

regex-cache

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Readme

regex-cache

Memoize the results of a call to the RegExp constructor. Whenever possible, avoiding repetitious runtime compilation of the same string and options can result in dramatic speed improvements.

Install with npm

npm i regex-cache --save

Usage

If the lib returns a function, you can wrap it like this:

var cache = require('regex-cache');
var regex = cache(require('some-regex-lib'));

Or, if the lib (or your own function) returns a regex, you can wrap it with a function first to achieve the same results.

Recommendations

do not use this if you are passing options
do use this if you are passing options and the logic to create the regex is extensive
do use this if you're not passing options and the lib returns a function (e.g. re().test(str))

Example benchmarks

Performance results for a random regex lib, mentions-regex, with and without regex-cache, and no options passed:

with regex-cache x 11,256,663 ops/sec ±0.59% (97 runs sampled)
without regex-cache x 1,812,916 ops/sec ±1.66% (24 runs sampled)

What it 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.

regex-cache is a simple way to cache the results of a previous call to the RegExp constructor to avoid unnecessary runtime compilation when both the string and options being passed have not changed.

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 to create the regex based on various inputs.

Run tests

Install dev dependencies:

npm i -d && npm test

Run benchmarks

Install dev dependencies:

npm i -d && npm run benchmarks

Contributing

Pull requests and stars are always welcome. For bugs and feature requests, please create an issue

Author

Jon Schlinkert

License

This file was generated by verb on February 09, 2015.