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    <title>DEV Community: TrèsAbhi</title>
    <description>The latest articles on DEV Community by TrèsAbhi (@tresabhi).</description>
    <link>https://dev.to/tresabhi</link>
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    <item>
      <title>How to stop infinite loop without breaking React's rule of hooks (useEffect)</title>
      <dc:creator>TrèsAbhi</dc:creator>
      <pubDate>Thu, 04 Nov 2021 18:04:34 +0000</pubDate>
      <link>https://dev.to/tresabhi/stop-infinite-loop-without-breaking-reacts-rule-of-hooks-useeffect-1k67</link>
      <guid>https://dev.to/tresabhi/stop-infinite-loop-without-breaking-reacts-rule-of-hooks-useeffect-1k67</guid>
      <description>&lt;p&gt;I have many different places where I have to use the same logic, so I have generalized my logic system into a class...&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="p"&gt;...&lt;/span&gt;
&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;contextLayer&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="k"&gt;new&lt;/span&gt; &lt;span class="nx"&gt;contextLayerCore&lt;/span&gt;&lt;span class="p"&gt;(...&lt;/span&gt;&lt;span class="nx"&gt;useState&lt;/span&gt;&lt;span class="p"&gt;([]));&lt;/span&gt;
&lt;span class="p"&gt;...&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;This class provides me with a bunch of functions like &lt;code&gt;addContext&lt;/code&gt;, &lt;code&gt;removeAll&lt;/code&gt;, etc. However, the &lt;code&gt;addContext&lt;/code&gt; function is a bit problematic...&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="p"&gt;...&lt;/span&gt;
&lt;span class="nx"&gt;addContext&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;context&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;listing&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;this&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;setState&lt;/span&gt;&lt;span class="p"&gt;([...&lt;/span&gt;&lt;span class="k"&gt;this&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;state&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;context&lt;/span&gt;&lt;span class="p"&gt;]);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;...&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Simple enough; all it does is append an object using the &lt;code&gt;setState&lt;/code&gt; function which should re-render any components using the &lt;code&gt;state&lt;/code&gt;. Here's the problem, this causes an infinite loop...&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="p"&gt;...&lt;/span&gt;
&lt;span class="k"&gt;this&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;setState&lt;/span&gt;&lt;span class="p"&gt;([...&lt;/span&gt;&lt;span class="k"&gt;this&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;state&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;context&lt;/span&gt;&lt;span class="p"&gt;]);&lt;/span&gt;
&lt;span class="c1"&gt;//                     ^&lt;/span&gt;
&lt;span class="c1"&gt;// also updates when state updates, hence re-runs the setState function&lt;/span&gt;
&lt;span class="p"&gt;...&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;This causes and infinite loop. I could using &lt;code&gt;useEffect(..., [])&lt;/code&gt; to make it not be dependant, however, this is a function inside a class, thus it breaks React's rules of hooks.&lt;/p&gt;

&lt;p&gt;I have to retain the functionality of this class, so I cannot move the function up into the component(s) as a lot of components use this class and would simply create duplicate code.&lt;/p&gt;

&lt;p&gt;And example of where it is used...&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="p"&gt;...&lt;/span&gt;
&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;ContextSuperContainer&lt;/span&gt; &lt;span class="nx"&gt;render&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;contextLayer&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;state&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;&lt;span class="p"&gt;...&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;What should I do? Is there an alternative of &lt;code&gt;useEffect&lt;/code&gt;? Should I be using a different system for this purpose?&lt;/p&gt;

&lt;h1&gt;
  
  
  Edit: Solution
&lt;/h1&gt;

&lt;p&gt;Convert it to a custom hook!&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="k"&gt;export&lt;/span&gt; &lt;span class="k"&gt;default&lt;/span&gt; &lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nx"&gt;useContextLayer&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;initialState&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nb"&gt;Array&lt;/span&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;listing&lt;/span&gt;&lt;span class="o"&gt;&amp;gt;&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;state&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;setState&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;useState&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;initialState&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="na"&gt;removeAll&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{...},&lt;/span&gt;
    &lt;span class="na"&gt;addContext&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{...},&lt;/span&gt;
    &lt;span class="c1"&gt;// doesn't even need an useEffect anymore&lt;/span&gt;
  &lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



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      <category>react</category>
      <category>typescript</category>
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