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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"><rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/AssignmentInOperand"</span> <span class="nt">/></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"><rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/AssignmentInOperand"</span><span class="nt">></span> <span class="nt"><properties></span> <span class="nt"><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">/></span> <span class="nt"><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">/></span> <span class="nt"><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">/></span> <span class="nt"><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">/></span> <span class="nt"><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">/></span> <span class="nt"><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">/></span> <span class="nt"></properties></span> <span class="nt"></rule></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"><</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"><</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"><rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/ForLoopsMustUseBraces"</span> <span class="nt">/></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"><rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/IfElseStmtsMustUseBraces"</span> <span class="nt">/></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"><rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/IfStmtsMustUseBraces"</span> <span class="nt">/></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"><rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/NoElseReturn"</span> <span class="nt">/></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"><rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/UnnecessaryBlock"</span> <span class="nt">/></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"><rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/UnnecessaryParentheses"</span> <span class="nt">/></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"><rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/UnreachableCode"</span> <span class="nt">/></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"><rule</span> <span class="na">ref=</span><span class="s">"category/ecmascript/codestyle.xml/WhileLoopsMustUseBraces"</span> <span class="nt">/></span> </code></pre></div></div> <div class="tags"> </div> </div> <footer> <hr /> <div> This documentation is written in markdown. <br /> If there is something missing or can be improved, edit this page on github and create a PR: <a target="_blank" href="https://github.com/pmd/pmd/blob/master/docs/../pmd-javascript/src/main/resources/category/ecmascript/codestyle.xml" role="button" ><i class="fab fa-github fa-lg"></i> Edit on GitHub</a > </div> <hr /> <div class="row"> <div class="col-lg-12 footer"> ©2024 PMD Open Source Project. 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