category.ecmascript.errorprone.xml Maven / Gradle / Ivy
<?xml version="1.0" encoding="UTF-8"?>
<ruleset name="Error Prone"
xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 https://pmd.sourceforge.io/ruleset_2_0_0.xsd">
<description>
Rules to detect constructs that are either broken, extremely confusing or prone to runtime errors.
</description>
<rule name="AvoidTrailingComma"
message="Avoid trailing commas in object or array literals"
language="ecmascript"
since="5.1"
class="net.sourceforge.pmd.lang.rule.xpath.XPathRule"
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_ecmascript_errorprone.html#avoidtrailingcomma">
<description>
This rule helps improve code portability due to differences in browser treatment of trailing commas in object or array literals.
</description>
<priority>1</priority>
<properties>
<property name="xpath">
<value>
<![CDATA[
//ObjectLiteral[$allowObjectLiteral = false() and @TrailingComma = true()]
|
//ArrayLiteral[$allowArrayLiteral = false() and @TrailingComma = true()]
]]>
</value>
</property>
<property name="allowObjectLiteral" type="Boolean" value="false" description="Allow a trailing comma within an object literal" />
<property name="allowArrayLiteral" type="Boolean" value="false" description="Allow a trailing comma within an array literal" />
</properties>
<example>
<![CDATA[
function(arg) {
var obj1 = { a : 1 }; // Ok
var arr1 = [ 1, 2 ]; // Ok
var obj2 = { a : 1, }; // Syntax error in some browsers!
var arr2 = [ 1, 2, ]; // Length 2 or 3 depending on the browser!
}
]]>
</example>
</rule>
<rule name="EqualComparison"
language="ecmascript"
since="5.0"
message="Use '==='/'!==' to compare with true/false or Numbers"
class="net.sourceforge.pmd.lang.rule.xpath.XPathRule"
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_ecmascript_errorprone.html#equalcomparison">
<description>
Using == in condition may lead to unexpected results, as the variables are automatically casted to be of the
same type. The === operator avoids the casting.
</description>
<priority>3</priority>
<properties>
<property name="xpath">
<value>
<![CDATA[
//InfixExpression[
(@Operator = '==' or @Operator = '!=')
and
(KeywordLiteral[@Literal = 'true' or @Literal = 'false'] or NumberLiteral)
]
]]>
</value>
</property>
</properties>
<example>
<![CDATA[
// Ok
if (someVar === true) {
...
}
// Ok
if (someVar !== 3) {
...
}
// Bad
if (someVar == true) {
...
}
// Bad
if (someVar != 3) {
...
}
]]>
</example>
</rule>
<rule name="InaccurateNumericLiteral"
language="ecmascript"
since="5.0"
message="The numeric literal ''{0}'' will have at different value at runtime."
class="net.sourceforge.pmd.lang.rule.xpath.XPathRule"
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_ecmascript_errorprone.html#inaccuratenumericliteral">
<description>
The numeric literal will have a different value at runtime, which can happen if you provide too much
precision in a floating point number. This may result in numeric calculations being in error.
[Numbers](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number) in JavaScript
are represented by 64bit double-precision floating point numbers internally and that's why there are some limits
to the available precision of the number.
See [Number.isSafeInteger()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isSafeInteger)
and [Number.EPSILON](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/EPSILON).
Note: This rule was named InnaccurateNumericLiteral before PMD 7.4.0.
</description>
<priority>2</priority>
<properties>
<property name="xpath">
<value>
<![CDATA[
//NumberLiteral[@Inaccurate = true()]
]]>
</value>
</property>
</properties>
<example>
<![CDATA[
var a = 9; // Ok
var b = 999999999999999; // Ok
var c = 999999999999999999999; // Not good
var w = 1.12e-4; // Ok
var x = 1.12; // Ok
var y = 1.1234567890123; // Ok
var z = 1.12345678901234567; // Not good
]]>
</example>
</rule>
<rule name="InnaccurateNumericLiteral" ref="InaccurateNumericLiteral" deprecated="true"/>
</ruleset>