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  # flat-cache
  > A stupidly simple key/value storage using files to persist the data
  
  [![NPM Version](http://img.shields.io/npm/v/flat-cache.svg?style=flat)](https://npmjs.org/package/flat-cache)
  [![Build Status](http://img.shields.io/travis/royriojas/flat-cache.svg?style=flat)](https://travis-ci.org/royriojas/flat-cache)
  
  ## install
  
  ```bash
  npm i --save flat-cache
  ```
  
  ## Usage
  
  ```js
  var flatCache = require('flat-cache')
  // loads the cache, if one does not exists for the given
  // Id a new one will be prepared to be created
  var cache = flatCache.load('cacheId');
  
  // sets a key on the cache
  cache.setKey('key', { foo: 'var' });
  
  // get a key from the cache
  cache.getKey('key') // { foo: 'var' }
  
  // fetch the entire persisted object
  cache.all() // { 'key': { foo: 'var' } }
  
  // remove a key
  cache.removeKey('key'); // removes a key from the cache
  
  // save it to disk
  cache.save(); // very important, if you don't save no changes will be persisted.
  // cache.save( true /* noPrune */) // can be used to prevent the removal of non visited keys
  
  // loads the cache from a given directory, if one does
  // not exists for the given Id a new one will be prepared to be created
  var cache = flatCache.load('cacheId', path.resolve('./path/to/folder'));
  
  // The following methods are useful to clear the cache
  // delete a given cache
  flatCache.clearCacheById('cacheId') // removes the cacheId document if one exists.
  
  // delete all cache
  flatCache.clearAll(); // remove the cache directory
  ```
  
  ## Motivation for this module
  
  I needed a super simple and dumb **in-memory cache** with optional disk persistance in order to make
  a script that will beutify files with `esformatter` only execute on the files that were changed since the last run.
  To make that possible we need to store the `fileSize` and `modificationTime` of the files. So a simple `key/value`
  storage was needed and Bam! this module was born.
  
  ## Important notes
  - If no directory is especified when the `load` method is called, a folder named `.cache` will be created
    inside the module directory when `cache.save` is called. If you're committing your `node_modules` to any vcs, you
    might want to ignore the default `.cache` folder, or specify a custom directory.
  - The values set on the keys of the cache should be `stringify-able` ones, meaning no circular references
  - All the changes to the cache state are done to memory
  - I could have used a timer or `Object.observe` to deliver the changes to disk, but I wanted to keep this module
    intentionally dumb and simple
  - Non visited keys are removed when `cache.save()` is called. If this is not desired, you can pass `true` to the save call
    like: `cache.save( true /* noPrune */ )`.
  
  ## License
  
  MIT
  
  ## Changelog
  
  [changelog](./changelog.md)