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diff --git a/node_modules/mem/readme.md b/node_modules/mem/readme.md deleted file mode 100644 index 7ebab84f0..000000000 --- a/node_modules/mem/readme.md +++ /dev/null @@ -1,147 +0,0 @@ -# mem [](https://travis-ci.org/sindresorhus/mem) - -> [Memoize](https://en.wikipedia.org/wiki/Memoization) functions - An optimization used to speed up consecutive function calls by caching the result of calls with identical input - - -## Install - -``` -$ npm install --save mem -``` - - -## Usage - -```js -const mem = require('mem'); - -let i = 0; -const counter = () => ++i; -const memoized = mem(counter); - -memoized('foo'); -//=> 1 - -// cached as it's the same arguments -memoized('foo'); -//=> 1 - -// not cached anymore as the arguments changed -memoized('bar'); -//=> 2 - -memoized('bar'); -//=> 2 -``` - -##### Works fine with promise returning functions - -```js -const mem = require('mem'); - -let i = 0; -const counter = () => Promise.resolve(++i); -const memoized = mem(counter); - -memoized().then(a => { - console.log(a); - //=> 1 - - memoized().then(b => { - // the return value didn't increase as it's cached - console.log(b); - //=> 1 - }); -}); -``` - -```js -const mem = require('mem'); -const got = require('got'); -const memGot = mem(got, {maxAge: 1000}); - -memGot('sindresorhus.com').then(() => { - // this call is cached - memGot('sindresorhus.com').then(() => { - setTimeout(() => { - // this call is not cached as the cache has expired - memGot('sindresorhus.com').then(() => {}); - }, 2000); - }); -}); -``` - - -## API - -### mem(fn, [options]) - -#### fn - -Type: `Function` - -Function to be memoized. - -#### options - -##### maxAge - -Type: `number`<br> -Default: `Infinity` - -Milliseconds until the cache expires. - -##### cacheKey - -Type: `Function` - -Determines the cache key for storing the result based on the function arguments. By default, if there's only one argument and it's a [primitive](https://developer.mozilla.org/en-US/docs/Glossary/Primitive), it's used directly as a key, otherwise it's all the function arguments JSON stringified as an array. - -You could for example change it to only cache on the first argument `x => JSON.stringify(x)`. - -##### cache - -Type: `Object`<br> -Default: `new Map()` - -Use a different cache storage. Must implement the following methods: `.has(key)`, `.get(key)`, `.set(key, value)`, and optionally `.clear()`. You could for example use a `WeakMap` instead. - -### mem.clear(fn) - -Clear all cached data of a memoized function. - -#### fn - -Type: `Function` - -Memoized function. - - -## Tips - -### Cache statistics - -If you want to know how many times your cache had a hit or a miss, you can make use of [stats-map](https://github.com/SamVerschueren/stats-map) as a replacement for the default cache. - -#### Example - -```js -const mem = require('mem'); -const StatsMap = require('stats-map'); -const got = require('got'); - -const cache = new StatsMap(); -const memGot = mem(got, {cache}); - -memGot('sindresorhus.com') - .then(() => memGot('sindresorhus.com')) - .then(() => memGot('sindresorhus.com')); - -console.log(cache.stats); -//=> {hits: 2, misses: 1} -``` - - -## License - -MIT © [Sindre Sorhus](https://sindresorhus.com) |