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<h1 id="flat-cache">flat-cache</h1>
<blockquote>
<p>A stupidly simple key/value storage using files to persist the
data</p>
</blockquote>
<h2 id="install">install</h2>
<div class="sourceCode" id="cb1"><pre
class="sourceCode bash"><code class="sourceCode bash"><span id="cb1-1"><a href="#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="ex">npm</span> i <span class="at">--save</span> flat-cache</span></code></pre></div>
<h2 id="usage">Usage</h2>
<div class="sourceCode" id="cb2"><pre class="sourceCode js"><code class="sourceCode javascript"><span id="cb2-1"><a href="#cb2-1" aria-hidden="true" tabindex="-1"></a><span class="kw">var</span> flatCache <span class="op">=</span> <span class="pp">require</span>(<span class="st">'flat-cache'</span>)</span>
<span id="cb2-2"><a href="#cb2-2" aria-hidden="true" tabindex="-1"></a><span class="co">// loads the cache, if one does not exists for the given</span></span>
<span id="cb2-3"><a href="#cb2-3" aria-hidden="true" tabindex="-1"></a><span class="co">// Id a new one will be prepared to be created</span></span>
<span id="cb2-4"><a href="#cb2-4" aria-hidden="true" tabindex="-1"></a><span class="kw">var</span> cache <span class="op">=</span> flatCache<span class="op">.</span><span class="fu">load</span>(<span class="st">'cacheId'</span>)<span class="op">;</span></span>
<span id="cb2-5"><a href="#cb2-5" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb2-6"><a href="#cb2-6" aria-hidden="true" tabindex="-1"></a><span class="co">// sets a key on the cache</span></span>
<span id="cb2-7"><a href="#cb2-7" aria-hidden="true" tabindex="-1"></a>cache<span class="op">.</span><span class="fu">setKey</span>(<span class="st">'key'</span><span class="op">,</span> { <span class="dt">foo</span><span class="op">:</span> <span class="st">'var'</span> })<span class="op">;</span></span>
<span id="cb2-8"><a href="#cb2-8" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb2-9"><a href="#cb2-9" aria-hidden="true" tabindex="-1"></a><span class="co">// get a key from the cache</span></span>
<span id="cb2-10"><a href="#cb2-10" aria-hidden="true" tabindex="-1"></a>cache<span class="op">.</span><span class="fu">getKey</span>(<span class="st">'key'</span>) <span class="co">// { foo: 'var' }</span></span>
<span id="cb2-11"><a href="#cb2-11" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb2-12"><a href="#cb2-12" aria-hidden="true" tabindex="-1"></a><span class="co">// fetch the entire persisted object</span></span>
<span id="cb2-13"><a href="#cb2-13" aria-hidden="true" tabindex="-1"></a>cache<span class="op">.</span><span class="fu">all</span>() <span class="co">// { 'key': { foo: 'var' } }</span></span>
<span id="cb2-14"><a href="#cb2-14" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb2-15"><a href="#cb2-15" aria-hidden="true" tabindex="-1"></a><span class="co">// remove a key</span></span>
<span id="cb2-16"><a href="#cb2-16" aria-hidden="true" tabindex="-1"></a>cache<span class="op">.</span><span class="fu">removeKey</span>(<span class="st">'key'</span>)<span class="op">;</span> <span class="co">// removes a key from the cache</span></span>
<span id="cb2-17"><a href="#cb2-17" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb2-18"><a href="#cb2-18" aria-hidden="true" tabindex="-1"></a><span class="co">// save it to disk</span></span>
<span id="cb2-19"><a href="#cb2-19" aria-hidden="true" tabindex="-1"></a>cache<span class="op">.</span><span class="fu">save</span>()<span class="op">;</span> <span class="co">// very important, if you don't save no changes will be persisted.</span></span>
<span id="cb2-20"><a href="#cb2-20" aria-hidden="true" tabindex="-1"></a><span class="co">// cache.save( true /* noPrune */) // can be used to prevent the removal of non visited keys</span></span>
<span id="cb2-21"><a href="#cb2-21" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb2-22"><a href="#cb2-22" aria-hidden="true" tabindex="-1"></a><span class="co">// loads the cache from a given directory, if one does</span></span>
<span id="cb2-23"><a href="#cb2-23" aria-hidden="true" tabindex="-1"></a><span class="co">// not exists for the given Id a new one will be prepared to be created</span></span>
<span id="cb2-24"><a href="#cb2-24" aria-hidden="true" tabindex="-1"></a><span class="kw">var</span> cache <span class="op">=</span> flatCache<span class="op">.</span><span class="fu">load</span>(<span class="st">'cacheId'</span><span class="op">,</span> path<span class="op">.</span><span class="fu">resolve</span>(<span class="st">'./path/to/folder'</span>))<span class="op">;</span></span>
<span id="cb2-25"><a href="#cb2-25" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb2-26"><a href="#cb2-26" aria-hidden="true" tabindex="-1"></a><span class="co">// The following methods are useful to clear the cache</span></span>
<span id="cb2-27"><a href="#cb2-27" aria-hidden="true" tabindex="-1"></a><span class="co">// delete a given cache</span></span>
<span id="cb2-28"><a href="#cb2-28" aria-hidden="true" tabindex="-1"></a>flatCache<span class="op">.</span><span class="fu">clearCacheById</span>(<span class="st">'cacheId'</span>) <span class="co">// removes the cacheId document if one exists.</span></span>
<span id="cb2-29"><a href="#cb2-29" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb2-30"><a href="#cb2-30" aria-hidden="true" tabindex="-1"></a><span class="co">// delete all cache</span></span>
<span id="cb2-31"><a href="#cb2-31" aria-hidden="true" tabindex="-1"></a>flatCache<span class="op">.</span><span class="fu">clearAll</span>()<span class="op">;</span> <span class="co">// remove the cache directory</span></span></code></pre></div>
<h2 id="motivation-for-this-module">Motivation for this module</h2>
<p>I needed a super simple and dumb <strong>in-memory cache</strong>
with optional disk persistance in order to make a script that will
beutify files with <code>esformatter</code> only execute on the files
that were changed since the last run. To make that possible we need to
store the <code>fileSize</code> and <code>modificationTime</code> of the
files. So a simple <code>key/value</code> storage was needed and Bam!
this module was born.</p>
<h2 id="important-notes">Important notes</h2>
<ul>
<li>If no directory is especified when the <code>load</code> method is
called, a folder named <code>.cache</code> will be created inside the
module directory when <code>cache.save</code> is called. If you're
committing your <code>node_modules</code> to any vcs, you might want to
ignore the default <code>.cache</code> folder, or specify a custom
directory.</li>
<li>The values set on the keys of the cache should be
<code>stringify-able</code> ones, meaning no circular references</li>
<li>All the changes to the cache state are done to memory</li>
<li>I could have used a timer or <code>Object.observe</code> to deliver
the changes to disk, but I wanted to keep this module intentionally dumb
and simple</li>
<li>Non visited keys are removed when <code>cache.save()</code> is
called. If this is not desired, you can pass <code>true</code> to the
save call like: <code>cache.save( true /* noPrune */ )</code>.</li>
</ul>
<h2 id="license">License</h2>
<p>MIT</p>
<h2 id="changelog">Changelog</h2>
<p><a href="./changelog.md">changelog</a></p>
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