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    <div class="sidebarTitleDate">Release date: 28-June-2024</div>
    
    
    
        
    
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            » Code Style   
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<div class="post-header">
   <h1 class="post-title-main">Code Style</h1>
</div>

<div class="post-content" data-github-edit-url="https://github.com/pmd/pmd/blob/master/docs/../pmd-javascript/src/main/resources/category/ecmascript/codestyle.xml">

   
    <div class="summary">Rules which enforce a specific coding style.</div>
   
    <details id="inline-toc-details">
        <summary>Table of Contents</summary>
        <div id="inline-toc"><!-- empty, move TOC here when screen size too small --></div>
    </details>

  <!-- DO NOT EDIT THIS FILE. This file is generated from file ../pmd-javascript/src/main/resources/category/ecmascript/codestyle.xml. -->
<h2 id="assignmentinoperand">AssignmentInOperand</h2>

<p><strong>Since:</strong> PMD 5.0</p>

<p><strong>Priority:</strong> Medium High (2)</p>

<p>Avoid assignments in operands; this can make code more complicated and harder to read.  This is sometime
indicative of the bug where the assignment operator ‘=’ was used instead of the equality operator ‘==’.</p>

<p><strong>This rule is defined by the following XPath expression:</strong></p>
<div class="language-xpath highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="o">//</span><span class="nt">IfStatement</span><span class="p">[</span><span class="nv">$allowIf</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="nf">false</span><span class="p">()]</span><span class="o">/</span><span class="kn">child::</span><span class="kr">node()</span><span class="p">[</span><span class="m">1</span><span class="p">]</span><span class="o">/</span><span class="kn">descendant-or-self::</span><span class="kr">node()</span><span class="p">[</span><span class="kn">self::</span><span class="nt">Assignment</span><span class="w"> </span><span class="ow">or</span><span class="w"> </span><span class="kn">self::</span><span class="nt">UpdateExpression</span><span class="p">[</span><span class="nv">$allowIncrementDecrement</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="nf">false</span><span class="p">()</span><span class="w"> </span><span class="ow">and</span><span class="w"> </span><span class="na">@Operator</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="p">(</span><span class="s1">'--'</span><span class="p">,</span><span class="w"> </span><span class="s1">'++'</span><span class="p">)]]</span><span class="w">
</span><span class="p">|</span><span class="w">
    </span><span class="o">//</span><span class="nt">WhileLoop</span><span class="p">[</span><span class="nv">$allowWhile</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="nf">false</span><span class="p">()]</span><span class="o">/</span><span class="kn">child::</span><span class="kr">node()</span><span class="p">[</span><span class="m">1</span><span class="p">]</span><span class="o">/</span><span class="kn">descendant-or-self::</span><span class="kr">node()</span><span class="p">[</span><span class="kn">self::</span><span class="nt">Assignment</span><span class="w"> </span><span class="ow">or</span><span class="w"> </span><span class="kn">self::</span><span class="nt">UpdateExpression</span><span class="p">[</span><span class="nv">$allowIncrementDecrement</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="nf">false</span><span class="p">()</span><span class="w"> </span><span class="ow">and</span><span class="w"> </span><span class="na">@Operator</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="p">(</span><span class="s1">'--'</span><span class="p">,</span><span class="w"> </span><span class="s1">'++'</span><span class="p">)]]</span><span class="w">
</span><span class="p">|</span><span class="w">
    </span><span class="o">//</span><span class="nt">DoLoop</span><span class="p">[</span><span class="nv">$allowWhile</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="nf">false</span><span class="p">()]</span><span class="o">/</span><span class="kn">child::</span><span class="kr">node()</span><span class="p">[</span><span class="m">2</span><span class="p">]</span><span class="o">/</span><span class="kn">descendant-or-self::</span><span class="kr">node()</span><span class="p">[</span><span class="kn">self::</span><span class="nt">Assignment</span><span class="w"> </span><span class="ow">or</span><span class="w"> </span><span class="kn">self::</span><span class="nt">UpdateExpression</span><span class="p">[</span><span class="nv">$allowIncrementDecrement</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="nf">false</span><span class="p">()</span><span class="w"> </span><span class="ow">and</span><span class="w"> </span><span class="na">@Operator</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="p">(</span><span class="s1">'--'</span><span class="p">,</span><span class="w"> </span><span class="s1">'++'</span><span class="p">)]]</span><span class="w">
</span><span class="p">|</span><span class="w">
    </span><span class="o">//</span><span class="nt">ForLoop</span><span class="p">[</span><span class="nv">$allowFor</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="nf">false</span><span class="p">()]</span><span class="o">/</span><span class="kn">child::</span><span class="kr">node()</span><span class="p">[</span><span class="m">2</span><span class="p">]</span><span class="o">/</span><span class="kn">descendant-or-self::</span><span class="kr">node()</span><span class="p">[</span><span class="kn">self::</span><span class="nt">Assignment</span><span class="w"> </span><span class="ow">or</span><span class="w"> </span><span class="kn">self::</span><span class="nt">UpdateExpression</span><span class="p">[</span><span class="nv">$allowIncrementDecrement</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="nf">false</span><span class="p">()</span><span class="w"> </span><span class="ow">and</span><span class="w"> </span><span class="na">@Operator</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="p">(</span><span class="s1">'--'</span><span class="p">,</span><span class="w"> </span><span class="s1">'++'</span><span class="p">)]]</span><span class="w">
</span><span class="p">|</span><span class="w">
   </span><span class="o">//</span><span class="nt">ConditionalExpression</span><span class="p">[</span><span class="nv">$allowTernary</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="nf">false</span><span class="p">()]</span><span class="o">/</span><span class="kn">child::</span><span class="kr">node()</span><span class="p">[</span><span class="m">1</span><span class="p">]</span><span class="o">/</span><span class="kn">descendant-or-self::</span><span class="kr">node()</span><span class="p">[</span><span class="kn">self::</span><span class="nt">Assignment</span><span class="w"> </span><span class="ow">or</span><span class="w"> </span><span class="kn">self::</span><span class="nt">UpdateExpression</span><span class="p">[</span><span class="nv">$allowIncrementDecrement</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="nf">false</span><span class="p">()</span><span class="w"> </span><span class="ow">and</span><span class="w"> </span><span class="na">@Operator</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="p">(</span><span class="s1">'--'</span><span class="p">,</span><span class="w"> </span><span class="s1">'++'</span><span class="p">)]]</span><span class="w">
</span><span class="p">|</span><span class="w">
   </span><span class="o">//</span><span class="nt">ConditionalExpression</span><span class="p">[</span><span class="nv">$allowTernaryResults</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="nf">false</span><span class="p">()]</span><span class="o">/</span><span class="kn">child::</span><span class="kr">node()</span><span class="p">[</span><span class="nf">position</span><span class="p">()</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="m">2</span><span class="w"> </span><span class="ow">or</span><span class="w"> </span><span class="nf">position</span><span class="p">()</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="m">3</span><span class="p">]</span><span class="o">/</span><span class="kn">descendant-or-self::</span><span class="kr">node()</span><span class="p">[</span><span class="kn">self::</span><span class="nt">Assignment</span><span class="w"> </span><span class="ow">or</span><span class="w"> </span><span class="kn">self::</span><span class="nt">UpdateExpression</span><span class="p">[</span><span class="nv">$allowIncrementDecrement</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="nf">false</span><span class="p">()</span><span class="w"> </span><span class="ow">and</span><span class="w"> </span><span class="na">@Operator</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="p">(</span><span class="s1">'--'</span><span class="p">,</span><span class="w"> </span><span class="s1">'++'</span><span class="p">)]]</span><span class="w">
</span></code></pre></div></div>

<p><strong>Example(s):</strong></p>

<div class="language-javascript highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="kd">var</span> <span class="nx">x</span> <span class="o">=</span> <span class="mi">2</span><span class="p">;</span>
<span class="c1">// Bad</span>
<span class="k">if</span> <span class="p">((</span><span class="nx">x</span> <span class="o">=</span> <span class="nx">getX</span><span class="p">())</span> <span class="o">==</span> <span class="mi">3</span><span class="p">)</span> <span class="p">{</span>
    <span class="nx">alert</span><span class="p">(</span><span class="dl">'</span><span class="s1">3!</span><span class="dl">'</span><span class="p">);</span>
<span class="p">}</span>

<span class="kd">function</span> <span class="nx">getX</span><span class="p">()</span> <span class="p">{</span>
    <span class="k">return</span> <span class="mi">3</span><span class="p">;</span>
<span class="p">}</span>
</code></pre></div></div>

<p><strong>This rule has the following properties:</strong></p>

<table>
  <thead>
    <tr>
      <th>Name</th>
      <th>Default Value</th>
      <th>Description</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>allowIf</td>
      <td>false</td>
      <td>Allow assignment within the conditional expression of an if statement</td>
    </tr>
    <tr>
      <td>allowFor</td>
      <td>false</td>
      <td>Allow assignment within the conditional expression of a for statement</td>
    </tr>
    <tr>
      <td>allowWhile</td>
      <td>false</td>
      <td>Allow assignment within the conditional expression of a while statement</td>
    </tr>
    <tr>
      <td>allowTernary</td>
      <td>false</td>
      <td>Allow assignment within the conditional expression of a ternary operator</td>
    </tr>
    <tr>
      <td>allowTernaryResults</td>
      <td>false</td>
      <td>Allow assignment within the result expressions of a ternary operator</td>
    </tr>
    <tr>
      <td>allowIncrementDecrement</td>
      <td>false</td>
      <td>Allow increment or decrement operators within the conditional expression of an if, for, or while statement</td>
    </tr>
  </tbody>
</table>

<p><strong>Use this rule with the default properties by just referencing it:</strong></p>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/AssignmentInOperand"</span> <span class="nt">/&gt;</span>
</code></pre></div></div>

<p><strong>Use this rule and customize it:</strong></p>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/AssignmentInOperand"</span><span class="nt">&gt;</span>
    <span class="nt">&lt;properties&gt;</span>
        <span class="nt">&lt;property</span> <span class="na">name=</span><span class="s">"allowIf"</span> <span class="na">value=</span><span class="s">"false"</span> <span class="nt">/&gt;</span>
        <span class="nt">&lt;property</span> <span class="na">name=</span><span class="s">"allowFor"</span> <span class="na">value=</span><span class="s">"false"</span> <span class="nt">/&gt;</span>
        <span class="nt">&lt;property</span> <span class="na">name=</span><span class="s">"allowWhile"</span> <span class="na">value=</span><span class="s">"false"</span> <span class="nt">/&gt;</span>
        <span class="nt">&lt;property</span> <span class="na">name=</span><span class="s">"allowTernary"</span> <span class="na">value=</span><span class="s">"false"</span> <span class="nt">/&gt;</span>
        <span class="nt">&lt;property</span> <span class="na">name=</span><span class="s">"allowTernaryResults"</span> <span class="na">value=</span><span class="s">"false"</span> <span class="nt">/&gt;</span>
        <span class="nt">&lt;property</span> <span class="na">name=</span><span class="s">"allowIncrementDecrement"</span> <span class="na">value=</span><span class="s">"false"</span> <span class="nt">/&gt;</span>
    <span class="nt">&lt;/properties&gt;</span>
<span class="nt">&lt;/rule&gt;</span>
</code></pre></div></div>

<h2 id="forloopsmustusebraces">ForLoopsMustUseBraces</h2>

<p><strong>Since:</strong> PMD 5.0</p>

<p><strong>Priority:</strong> Medium (3)</p>

<p>Avoid using ‘for’ statements without using curly braces.</p>

<p><strong>This rule is defined by the following XPath expression:</strong></p>
<div class="language-xpath highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="o">//</span><span class="nt">ForLoop</span><span class="p">[</span><span class="ow">not</span><span class="p">(</span><span class="kn">child::</span><span class="nt">Scope</span><span class="p">)]</span><span class="w">
</span><span class="p">|</span><span class="w">
</span><span class="o">//</span><span class="nt">ForInLoop</span><span class="p">[</span><span class="ow">not</span><span class="p">(</span><span class="kn">child::</span><span class="nt">Scope</span><span class="p">)]</span><span class="w">
</span></code></pre></div></div>

<p><strong>Example(s):</strong></p>

<div class="language-javascript highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="c1">// Ok</span>
<span class="k">for</span> <span class="p">(</span><span class="kd">var</span> <span class="nx">i</span> <span class="o">=</span> <span class="mi">0</span><span class="p">;</span> <span class="nx">i</span> <span class="o">&lt;</span> <span class="mi">42</span><span class="p">;</span> <span class="nx">i</span><span class="o">++</span><span class="p">)</span> <span class="p">{</span>
    <span class="nx">foo</span><span class="p">();</span>
<span class="p">}</span>

<span class="c1">// Bad</span>
<span class="k">for</span> <span class="p">(</span><span class="kd">var</span> <span class="nx">i</span> <span class="o">=</span> <span class="mi">0</span><span class="p">;</span> <span class="nx">i</span> <span class="o">&lt;</span> <span class="mi">42</span><span class="p">;</span> <span class="nx">i</span><span class="o">++</span><span class="p">)</span>
    <span class="nx">foo</span><span class="p">();</span>
</code></pre></div></div>

<p><strong>Use this rule by referencing it:</strong></p>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/ForLoopsMustUseBraces"</span> <span class="nt">/&gt;</span>
</code></pre></div></div>

<h2 id="ifelsestmtsmustusebraces">IfElseStmtsMustUseBraces</h2>

<p><strong>Since:</strong> PMD 5.0</p>

<p><strong>Priority:</strong> Medium (3)</p>

<p>Avoid using if..else statements without using curly braces.</p>

<p><strong>This rule is defined by the following XPath expression:</strong></p>
<div class="language-xpath highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="o">//</span><span class="nt">ExpressionStatement</span><span class="p">[</span><span class="kn">parent::</span><span class="nt">IfStatement</span><span class="p">[</span><span class="na">@Else</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="nf">true</span><span class="p">()]]</span><span class="w">
   </span><span class="p">[</span><span class="ow">not</span><span class="p">(</span><span class="kn">child::</span><span class="nt">Scope</span><span class="p">)]</span><span class="w">
   </span><span class="p">[</span><span class="ow">not</span><span class="p">(</span><span class="kn">child::</span><span class="nt">IfStatement</span><span class="p">)]</span><span class="w">
</span></code></pre></div></div>

<p><strong>Example(s):</strong></p>

<div class="language-javascript highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="c1">// Ok</span>
<span class="k">if</span> <span class="p">(</span><span class="nx">foo</span><span class="p">)</span> <span class="p">{</span>
    <span class="nx">x</span><span class="o">++</span><span class="p">;</span>
<span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
    <span class="nx">y</span><span class="o">++</span><span class="p">;</span>
<span class="p">}</span>

<span class="c1">// Bad</span>
<span class="k">if</span> <span class="p">(</span><span class="nx">foo</span><span class="p">)</span>
    <span class="nx">x</span><span class="o">++</span><span class="p">;</span>
<span class="k">else</span>
    <span class="nx">y</span><span class="o">++</span><span class="p">;</span>
</code></pre></div></div>

<p><strong>Use this rule by referencing it:</strong></p>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/IfElseStmtsMustUseBraces"</span> <span class="nt">/&gt;</span>
</code></pre></div></div>

<h2 id="ifstmtsmustusebraces">IfStmtsMustUseBraces</h2>

<p><strong>Since:</strong> PMD 5.0</p>

<p><strong>Priority:</strong> Medium (3)</p>

<p>Avoid using if statements without using curly braces.</p>

<p><strong>This rule is defined by the following XPath expression:</strong></p>
<div class="language-xpath highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="o">//</span><span class="nt">IfStatement</span><span class="p">[</span><span class="na">@Else</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="nf">false</span><span class="p">()</span><span class="w"> </span><span class="ow">and</span><span class="w"> </span><span class="ow">not</span><span class="p">(</span><span class="kn">child::</span><span class="nt">Scope</span><span class="p">)]</span><span class="w">
</span></code></pre></div></div>

<p><strong>Example(s):</strong></p>

<div class="language-javascript highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="c1">// Ok</span>
<span class="k">if</span> <span class="p">(</span><span class="nx">foo</span><span class="p">)</span> <span class="p">{</span>
    <span class="nx">x</span><span class="o">++</span><span class="p">;</span>
<span class="p">}</span>

<span class="c1">// Bad</span>
<span class="k">if</span> <span class="p">(</span><span class="nx">foo</span><span class="p">)</span>
    <span class="nx">x</span><span class="o">++</span><span class="p">;</span>
</code></pre></div></div>

<p><strong>Use this rule by referencing it:</strong></p>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/IfStmtsMustUseBraces"</span> <span class="nt">/&gt;</span>
</code></pre></div></div>

<h2 id="noelsereturn">NoElseReturn</h2>

<p><strong>Since:</strong> PMD 5.5.0</p>

<p><strong>Priority:</strong> Medium (3)</p>

<p>The else block in a if-else-construct is unnecessary if the <code class="language-plaintext highlighter-rouge">if</code> block contains a return.
Then the content of the else block can be put outside.</p>

<p>See also: <a href="http://eslint.org/docs/rules/no-else-return">http://eslint.org/docs/rules/no-else-return</a></p>

<p><strong>This rule is defined by the following XPath expression:</strong></p>
<div class="language-xpath highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="o">//</span><span class="nt">IfStatement</span><span class="p">[</span><span class="na">@Else</span><span class="err">=</span><span class="nf">true</span><span class="p">()][</span><span class="nt">Scope</span><span class="p">[</span><span class="m">1</span><span class="p">]</span><span class="o">/</span><span class="nt">ReturnStatement</span><span class="p">]</span><span class="w">
</span></code></pre></div></div>

<p><strong>Example(s):</strong></p>

<div class="language-javascript highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="c1">// Bad:</span>
<span class="k">if</span> <span class="p">(</span><span class="nx">x</span><span class="p">)</span> <span class="p">{</span>
    <span class="k">return</span> <span class="nx">y</span><span class="p">;</span>
<span class="p">}</span> <span class="k">else</span> <span class="p">{</span>
    <span class="k">return</span> <span class="nx">z</span><span class="p">;</span>
<span class="p">}</span>

<span class="c1">// Good:</span>
<span class="k">if</span> <span class="p">(</span><span class="nx">x</span><span class="p">)</span> <span class="p">{</span>
    <span class="k">return</span> <span class="nx">y</span><span class="p">;</span>
<span class="p">}</span>
<span class="k">return</span> <span class="nx">z</span><span class="p">;</span>
</code></pre></div></div>

<p><strong>Use this rule by referencing it:</strong></p>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/NoElseReturn"</span> <span class="nt">/&gt;</span>
</code></pre></div></div>

<h2 id="unnecessaryblock">UnnecessaryBlock</h2>

<p><strong>Since:</strong> PMD 5.0</p>

<p><strong>Priority:</strong> Medium (3)</p>

<p>An unnecessary Block is present.  Such Blocks are often used in other languages to
introduce a new variable scope.  Blocks do not behave like this in ECMAScipt, and using them can
be misleading.  Considering removing this unnecessary Block.</p>

<p><strong>This rule is defined by the following XPath expression:</strong></p>
<div class="language-xpath highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="o">/</span><span class="nt">AstRoot</span><span class="o">/</span><span class="nt">Scope</span><span class="p">[</span><span class="ow">not</span><span class="p">(</span><span class="nn">preceding:</span><span class="err">:</span><span class="nt">EmptyStatement</span><span class="p">)]</span><span class="w">
                    </span><span class="p">|</span><span class="w"> </span><span class="o">//</span><span class="nt">SwitchCase</span><span class="p">[</span><span class="nt">Scope</span><span class="p">]</span><span class="w">
                    </span><span class="p">|</span><span class="w"> </span><span class="err">//</span><span class="p">(</span><span class="nt">Scope</span><span class="p">|</span><span class="nt">Block</span><span class="p">)[</span><span class="nt">Scope</span><span class="p">|</span><span class="nt">Block</span><span class="p">][</span><span class="nf">count</span><span class="p">(</span><span class="err">*</span><span class="p">)</span><span class="w"> </span><span class="err">=</span><span class="w"> </span><span class="m">1</span><span class="p">]</span><span class="w">
</span></code></pre></div></div>

<p><strong>Example(s):</strong></p>

<div class="language-javascript highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="k">if</span> <span class="p">(</span><span class="nx">foo</span><span class="p">)</span> <span class="p">{</span>
    <span class="c1">// Ok</span>
<span class="p">}</span>
<span class="k">if</span> <span class="p">(</span><span class="nx">bar</span><span class="p">)</span> <span class="p">{</span>
    <span class="p">{</span>
        <span class="c1">// Bad</span>
    <span class="p">}</span>
<span class="p">}</span>
</code></pre></div></div>

<p><strong>Use this rule by referencing it:</strong></p>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/UnnecessaryBlock"</span> <span class="nt">/&gt;</span>
</code></pre></div></div>

<h2 id="unnecessaryparentheses">UnnecessaryParentheses</h2>

<p><strong>Since:</strong> PMD 5.0</p>

<p><strong>Priority:</strong> Medium Low (4)</p>

<p>Unnecessary parentheses should be removed.</p>

<p><strong>This rule is defined by the following XPath expression:</strong></p>
<div class="language-xpath highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="o">//</span><span class="nt">ParenthesizedExpression</span><span class="o">/</span><span class="nt">ParenthesizedExpression</span><span class="w">
</span></code></pre></div></div>

<p><strong>Example(s):</strong></p>

<div class="language-javascript highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="kd">var</span> <span class="nx">x</span> <span class="o">=</span> <span class="mi">1</span><span class="p">;</span> <span class="c1">// Ok</span>
<span class="kd">var</span> <span class="nx">y</span> <span class="o">=</span> <span class="p">(</span><span class="mi">1</span> <span class="o">+</span> <span class="mi">1</span><span class="p">);</span> <span class="c1">// Ok</span>
<span class="kd">var</span> <span class="nx">z</span> <span class="o">=</span> <span class="p">((</span><span class="mi">1</span> <span class="o">+</span> <span class="mi">1</span><span class="p">));</span> <span class="c1">// Bad</span>
</code></pre></div></div>

<p><strong>Use this rule by referencing it:</strong></p>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/UnnecessaryParentheses"</span> <span class="nt">/&gt;</span>
</code></pre></div></div>

<h2 id="unreachablecode">UnreachableCode</h2>

<p><strong>Since:</strong> PMD 5.0</p>

<p><strong>Priority:</strong> High (1)</p>

<p>A ‘return’, ‘break’, ‘continue’, or ‘throw’ statement should be the last in a block. Statements after these
will never execute.  This is a bug, or extremely poor style.</p>

<p><strong>This rule is defined by the following XPath expression:</strong></p>
<div class="language-xpath highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="o">//</span><span class="nt">ReturnStatement</span><span class="p">[</span><span class="kn">following-sibling::</span><span class="kr">node()</span><span class="p">]</span><span class="w">
</span><span class="p">|</span><span class="w">
    </span><span class="o">//</span><span class="nt">ContinueStatement</span><span class="p">[</span><span class="kn">following-sibling::</span><span class="kr">node()</span><span class="p">]</span><span class="w">
</span><span class="p">|</span><span class="w">
    </span><span class="o">//</span><span class="nt">BreakStatement</span><span class="p">[</span><span class="kn">following-sibling::</span><span class="kr">node()</span><span class="p">]</span><span class="w">
</span><span class="p">|</span><span class="w">
    </span><span class="o">//</span><span class="nt">ThrowStatement</span><span class="p">[</span><span class="kn">following-sibling::</span><span class="kr">node()</span><span class="p">]</span><span class="w">
</span></code></pre></div></div>

<p><strong>Example(s):</strong></p>

<div class="language-javascript highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="c1">// Ok</span>
<span class="kd">function</span> <span class="nx">foo</span><span class="p">()</span> <span class="p">{</span>
   <span class="k">return</span> <span class="mi">1</span><span class="p">;</span>
<span class="p">}</span>
<span class="c1">// Bad</span>
<span class="kd">function</span> <span class="nx">bar</span><span class="p">()</span> <span class="p">{</span>
   <span class="kd">var</span> <span class="nx">x</span> <span class="o">=</span> <span class="mi">1</span><span class="p">;</span>
   <span class="k">return</span> <span class="nx">x</span><span class="p">;</span>
   <span class="nx">x</span> <span class="o">=</span> <span class="mi">2</span><span class="p">;</span>
<span class="p">}</span>
</code></pre></div></div>

<p><strong>Use this rule by referencing it:</strong></p>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/UnreachableCode"</span> <span class="nt">/&gt;</span>
</code></pre></div></div>

<h2 id="whileloopsmustusebraces">WhileLoopsMustUseBraces</h2>

<p><strong>Since:</strong> PMD 5.0</p>

<p><strong>Priority:</strong> Medium (3)</p>

<p>Avoid using ‘while’ statements without using curly braces.</p>

<p><strong>This rule is defined by the following XPath expression:</strong></p>
<div class="language-xpath highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="o">//</span><span class="nt">WhileLoop</span><span class="p">[</span><span class="ow">not</span><span class="p">(</span><span class="kn">child::</span><span class="nt">Scope</span><span class="p">)]</span><span class="w">
</span></code></pre></div></div>

<p><strong>Example(s):</strong></p>

<div class="language-javascript highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="c1">// Ok</span>
<span class="k">while</span> <span class="p">(</span><span class="kc">true</span><span class="p">)</span> <span class="p">{</span>
    <span class="nx">x</span><span class="o">++</span><span class="p">;</span>
<span class="p">}</span>

<span class="c1">// Bad</span>
<span class="k">while</span> <span class="p">(</span><span class="kc">true</span><span class="p">)</span>
    <span class="nx">x</span><span class="o">++</span><span class="p">;</span>
</code></pre></div></div>

<p><strong>Use this rule by referencing it:</strong></p>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/WhileLoopsMustUseBraces"</span> <span class="nt">/&gt;</span>
</code></pre></div></div>



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