checkstyle.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
    "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
    "https://checkstyle.org/dtds/configuration_1_3.dtd">

<!-- Checkstyle configuration for the Java port.
     A focused, low-noise rule set: it targets real maintainability problems
     (unused imports, empty blocks, equals/hashCode, fall-through) rather than
     full formatting enforcement. The brace-placement / braceless-`if` rules
     (NeedBraces, LeftCurly, RightCurly) are intentionally off — this port
     mirrors the canonical TypeScript source layout, which uses braceless
     single-statement `if`s and TS-style brace placement throughout. -->
<module name="Checker">
  <property name="charset" value="UTF-8"/>
  <property name="severity" value="warning"/>
  <property name="fileExtensions" value="java"/>

  <module name="LineLength">
    <property name="max" value="140"/>
    <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://"/>
  </module>

  <module name="TreeWalker">
    <!-- Imports -->
    <module name="UnusedImports"/>
    <module name="RedundantImport"/>
    <module name="AvoidStarImport"/>

    <!-- Blocks -->
    <module name="EmptyBlock">
      <property name="option" value="text"/>
    </module>

    <!-- Coding problems -->
    <module name="EqualsHashCode"/>
    <module name="FallThrough"/>
    <module name="MissingSwitchDefault"/>
    <module name="SimplifyBooleanExpression"/>
    <module name="SimplifyBooleanReturn"/>
    <module name="StringLiteralEquality"/>
    <module name="EmptyStatement"/>
    <!-- OneStatementPerLine off: the in-tree `_jsonifyInner` (and a few
         other tight TS-mirror sites) use `if (cond) { x; return; }`
         one-liners that mirror the canonical TS layout. The rest of the
         braceless-`if` exception note above applies. -->
    <module name="UpperEll"/>
    <module name="ModifierOrder"/>

    <!-- Whitespace -->
    <module name="WhitespaceAfter"/>
    <module name="NoWhitespaceBefore"/>
    <module name="GenericWhitespace"/>
  </module>
</module>