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