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<h1 id="read-storage">Read storage</h1>
<p>Many important variables are available through the storage API. This example shows how to call a few of those APIs.</p>
<pre><code class="lang-javascript"><div class="sunlight-container sunlight-theme-gitbook"><div class="sunlight-code-container"><pre class="sunlight-highlight-javascript sunlight-highlighted"><span class="sunlight-javascript"><span class="sunlight-reservedWord">const</span>&#xA0;<span class="sunlight-ident">BN</span>&#xA0;<span class="sunlight-operator">=</span>&#xA0;<span class="sunlight-ident">require</span><span class="sunlight-punctuation">(</span><span class="sunlight-string">&apos;bn.js&apos;</span><span class="sunlight-punctuation">)</span><span class="sunlight-punctuation">;</span>
<span class="sunlight-reservedWord">const</span>&#xA0;<span class="sunlight-ident">Rpc</span>&#xA0;<span class="sunlight-operator">=</span>&#xA0;<span class="sunlight-ident">require</span><span class="sunlight-punctuation">(</span><span class="sunlight-string">&apos;@polkadot/rpc-core&apos;</span><span class="sunlight-punctuation">)</span><span class="sunlight-operator">.</span><span class="sunlight-keyword">default</span><span class="sunlight-punctuation">;</span>
<span class="sunlight-reservedWord">const</span>&#xA0;<span class="sunlight-ident">WsProvider</span>&#xA0;<span class="sunlight-operator">=</span>&#xA0;<span class="sunlight-ident">require</span><span class="sunlight-punctuation">(</span><span class="sunlight-string">&apos;@polkadot/rpc-provider/ws&apos;</span><span class="sunlight-punctuation">)</span><span class="sunlight-operator">.</span><span class="sunlight-keyword">default</span><span class="sunlight-punctuation">;</span>
<span class="sunlight-reservedWord">const</span>&#xA0;<span class="sunlight-ident">storage</span>&#xA0;<span class="sunlight-operator">=</span>&#xA0;<span class="sunlight-ident">require</span><span class="sunlight-punctuation">(</span><span class="sunlight-string">&apos;@polkadot/storage&apos;</span><span class="sunlight-punctuation">)</span><span class="sunlight-operator">.</span><span class="sunlight-keyword">default</span><span class="sunlight-punctuation">;</span>
<span class="sunlight-reservedWord">const</span>&#xA0;<span class="sunlight-ident">provider</span>&#xA0;<span class="sunlight-operator">=</span>&#xA0;<span class="sunlight-keyword">new</span>&#xA0;<span class="sunlight-ident">WsProvider</span><span class="sunlight-punctuation">(</span><span class="sunlight-string">&apos;ws://127.0.0.1:9944&apos;</span><span class="sunlight-punctuation">)</span><span class="sunlight-punctuation">;</span>
<span class="sunlight-reservedWord">const</span>&#xA0;<span class="sunlight-ident">api</span>&#xA0;<span class="sunlight-operator">=</span>&#xA0;<span class="sunlight-keyword">new</span>&#xA0;<span class="sunlight-ident">Rpc</span><span class="sunlight-punctuation">(</span><span class="sunlight-ident">provider</span><span class="sunlight-punctuation">)</span><span class="sunlight-punctuation">;</span>
<span class="sunlight-ident">async</span>&#xA0;<span class="sunlight-keyword">function</span>&#xA0;<span class="sunlight-named-ident">getAccountIndex</span>&#xA0;<span class="sunlight-punctuation">(</span><span class="sunlight-ident">address</span><span class="sunlight-punctuation">)</span>&#xA0;<span class="sunlight-punctuation">{</span>
&#xA0;&#xA0;<span class="sunlight-keyword">return</span>&#xA0;<span class="sunlight-ident">api</span><span class="sunlight-operator">.</span><span class="sunlight-ident">state</span><span class="sunlight-operator">.</span><span class="sunlight-ident">getStorage</span><span class="sunlight-punctuation">(</span><span class="sunlight-punctuation">[</span><span class="sunlight-ident">storage</span><span class="sunlight-operator">.</span><span class="sunlight-ident">system</span><span class="sunlight-operator">.</span><span class="sunlight-reservedWord">public</span><span class="sunlight-operator">.</span><span class="sunlight-ident">accountIndexOf</span><span class="sunlight-punctuation">,</span>&#xA0;<span class="sunlight-ident">address</span><span class="sunlight-punctuation">]</span><span class="sunlight-punctuation">)</span><span class="sunlight-punctuation">;</span>
<span class="sunlight-punctuation">}</span>
<span class="sunlight-ident">async</span>&#xA0;<span class="sunlight-keyword">function</span>&#xA0;<span class="sunlight-named-ident">getValidators</span>&#xA0;<span class="sunlight-punctuation">(</span><span class="sunlight-punctuation">)</span>&#xA0;<span class="sunlight-punctuation">{</span>
&#xA0;&#xA0;<span class="sunlight-keyword">return</span>&#xA0;<span class="sunlight-ident">api</span><span class="sunlight-operator">.</span><span class="sunlight-ident">state</span><span class="sunlight-operator">.</span><span class="sunlight-ident">getStorage</span><span class="sunlight-punctuation">(</span><span class="sunlight-punctuation">[</span><span class="sunlight-ident">storage</span><span class="sunlight-operator">.</span><span class="sunlight-ident">session</span><span class="sunlight-operator">.</span><span class="sunlight-reservedWord">public</span><span class="sunlight-operator">.</span><span class="sunlight-ident">validators</span><span class="sunlight-punctuation">]</span><span class="sunlight-punctuation">)</span><span class="sunlight-punctuation">;</span>
<span class="sunlight-punctuation">}</span>
<span class="sunlight-ident">async</span>&#xA0;<span class="sunlight-keyword">function</span>&#xA0;<span class="sunlight-named-ident">getBlockPeriod</span>&#xA0;<span class="sunlight-punctuation">(</span><span class="sunlight-punctuation">)</span>&#xA0;<span class="sunlight-punctuation">{</span>
&#xA0;&#xA0;<span class="sunlight-keyword">return</span>&#xA0;<span class="sunlight-ident">api</span><span class="sunlight-operator">.</span><span class="sunlight-ident">state</span><span class="sunlight-operator">.</span><span class="sunlight-ident">getStorage</span><span class="sunlight-punctuation">(</span><span class="sunlight-punctuation">[</span><span class="sunlight-ident">storage</span><span class="sunlight-operator">.</span><span class="sunlight-ident">timestamp</span><span class="sunlight-operator">.</span><span class="sunlight-reservedWord">public</span><span class="sunlight-operator">.</span><span class="sunlight-ident">blockPeriod</span><span class="sunlight-punctuation">]</span><span class="sunlight-punctuation">)</span><span class="sunlight-punctuation">;</span>
<span class="sunlight-punctuation">}</span>
<span class="sunlight-ident">async</span>&#xA0;<span class="sunlight-keyword">function</span>&#xA0;<span class="sunlight-named-ident">main</span>&#xA0;<span class="sunlight-punctuation">(</span><span class="sunlight-punctuation">)</span>&#xA0;<span class="sunlight-punctuation">{</span>
&#xA0;&#xA0;<span class="sunlight-reservedWord">const</span>&#xA0;<span class="sunlight-ident">address</span>&#xA0;<span class="sunlight-operator">=</span>&#xA0;<span class="sunlight-string">&apos;5GoKvZWG5ZPYL1WUovuHW3zJBWBP5eT8CbqjdRY4Q6iMaDtZ&apos;</span><span class="sunlight-punctuation">;</span>
&#xA0;&#xA0;<span class="sunlight-reservedWord">const</span>&#xA0;<span class="sunlight-ident">validators</span>&#xA0;<span class="sunlight-operator">=</span>&#xA0;<span class="sunlight-ident">await</span>&#xA0;<span class="sunlight-ident">getValidators</span><span class="sunlight-punctuation">(</span><span class="sunlight-punctuation">)</span><span class="sunlight-punctuation">;</span>
&#xA0;&#xA0;<span class="sunlight-reservedWord">const</span>&#xA0;<span class="sunlight-ident">index</span>&#xA0;<span class="sunlight-operator">=</span>&#xA0;<span class="sunlight-ident">await</span>&#xA0;<span class="sunlight-ident">getAccountIndex</span><span class="sunlight-punctuation">(</span><span class="sunlight-ident">address</span><span class="sunlight-punctuation">)</span><span class="sunlight-punctuation">;</span>
&#xA0;&#xA0;<span class="sunlight-reservedWord">const</span>&#xA0;<span class="sunlight-ident">blockPeriod</span>&#xA0;<span class="sunlight-operator">=</span>&#xA0;<span class="sunlight-ident">await</span>&#xA0;<span class="sunlight-ident">getBlockPeriod</span><span class="sunlight-punctuation">(</span><span class="sunlight-punctuation">)</span><span class="sunlight-punctuation">;</span>
&#xA0;&#xA0;<span class="sunlight-ident">console</span><span class="sunlight-operator">.</span><span class="sunlight-ident">log</span><span class="sunlight-punctuation">(</span><span class="sunlight-punctuation">`</span><span class="sunlight-ident">BlockPeriod</span><span class="sunlight-operator">:</span>&#xA0;<span class="sunlight-ident">$</span><span class="sunlight-punctuation">{</span><span class="sunlight-keyword">new</span>&#xA0;<span class="sunlight-ident">BN</span><span class="sunlight-punctuation">(</span><span class="sunlight-ident">blockPeriod</span><span class="sunlight-punctuation">)</span><span class="sunlight-operator">.</span><span class="sunlight-ident">toString</span><span class="sunlight-punctuation">(</span><span class="sunlight-number">10</span><span class="sunlight-punctuation">)</span><span class="sunlight-punctuation">}</span>&#xA0;<span class="sunlight-ident">seconds</span><span class="sunlight-punctuation">`</span><span class="sunlight-punctuation">)</span><span class="sunlight-punctuation">;</span>
&#xA0;&#xA0;<span class="sunlight-ident">console</span><span class="sunlight-operator">.</span><span class="sunlight-ident">log</span><span class="sunlight-punctuation">(</span><span class="sunlight-punctuation">`</span><span class="sunlight-ident">Account</span>&#xA0;<span class="sunlight-ident">Index</span>&#xA0;<span class="sunlight-ident">of</span>&#xA0;<span class="sunlight-ident">$</span><span class="sunlight-punctuation">{</span><span class="sunlight-ident">address</span><span class="sunlight-punctuation">}</span><span class="sunlight-operator">:</span>&#xA0;<span class="sunlight-ident">$</span><span class="sunlight-punctuation">{</span><span class="sunlight-ident">index</span><span class="sunlight-operator">.</span><span class="sunlight-ident">toString</span><span class="sunlight-punctuation">(</span><span class="sunlight-number">10</span><span class="sunlight-punctuation">)</span><span class="sunlight-punctuation">}</span><span class="sunlight-punctuation">`</span><span class="sunlight-punctuation">)</span><span class="sunlight-punctuation">;</span>
&#xA0;&#xA0;<span class="sunlight-ident">console</span><span class="sunlight-operator">.</span><span class="sunlight-ident">log</span><span class="sunlight-punctuation">(</span><span class="sunlight-string">&apos;Current&#xA0;validators&apos;</span><span class="sunlight-punctuation">,</span>&#xA0;<span class="sunlight-ident">validators</span><span class="sunlight-punctuation">)</span><span class="sunlight-punctuation">;</span>
<span class="sunlight-punctuation">}</span>
<span class="sunlight-ident">main</span><span class="sunlight-punctuation">(</span><span class="sunlight-punctuation">)</span><span class="sunlight-operator">.</span><span class="sunlight-keyword">finally</span><span class="sunlight-punctuation">(</span><span class="sunlight-ident">_</span>&#xA0;<span class="sunlight-operator">=</span><span class="sunlight-operator">&gt;</span>&#xA0;<span class="sunlight-ident">process</span><span class="sunlight-operator">.</span><span class="sunlight-ident">exit</span><span class="sunlight-punctuation">(</span><span class="sunlight-punctuation">)</span><span class="sunlight-punctuation">)</span><span class="sunlight-punctuation">;</span>
</span></pre></div></div></code></pre>
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