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# flat-cache
> A stupidly simple key/value storage using files to persist the data
[](https://npmjs.org/package/flat-cache)
[](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)
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