YUI Compressor Maven Plugin

Maven plugin that compresses (minifies, obfuscates and aggregates) JavaScript and CSS files using YUI Compressor, and validates JavaScript files with JSLint.

This project is a fork of net.alchim31.maven:yuicompressor-maven-plugin, maintained by the CodeLibs Project for continued development and modern Maven support. It is published as org.codelibs.maven:yuicompressor-maven-plugin and builds on org.codelibs:yuicompressor 2.4.11.

Requirements

• Java 11 or later
• Maven 3.8.1 or later

Getting Started

Add the plugin to the build section of your pom.xml:

<build>
  <plugins>
    <plugin>
      <groupId>org.codelibs.maven</groupId>
      <artifactId>yuicompressor-maven-plugin</artifactId>
      <version>2.0.1</version>
      <executions>
        <execution>
          <goals>
            <goal>compress</goal>
          </goals>
        </execution>
      </executions>
    </plugin>
  </plugins>
</build>

By default the compress goal picks up every **/*.js and **/*.css file under src/main/js, the project resource directories and src/main/webapp, and writes the compressed copy into the matching output directory (target/classes, or the exploded web application for src/main/webapp) with a -min suffix: app.js becomes app-min.js.

Goals

Goal	Default phase	Description
compress	process-resources	Compresses JavaScript and CSS files, and optionally aggregates and gzips them.
jslint	process-resources	Checks JavaScript files with JSLint.

Both goals are thread-safe and support incremental builds in Eclipse through the m2e BuildContext API.

Configuration

Source selection

These parameters are shared by both goals.

Parameter	Default	Description
sourceDirectory	${project.build.sourceDirectory}/../js	Additional JavaScript source directory, for projects laid out as src/main/js.
warSourceDirectory	${basedir}/src/main/webapp	Web application source directory.
webappDirectory	${project.build.directory}/${project.build.finalName}	Directory the web application is built into.
outputDirectory	${project.build.outputDirectory}	Directory the processed files are written to.
includes	**/*.js, **/*.css (compress); **/*.js (jslint)	Include patterns. Replaces the defaults when set.
excludes	none	Additional exclude patterns.
excludeResources	false	Skip files under the project resource directories.
excludeWarSourceDirectory	false	Skip files under warSourceDirectory.
useProcessedResources	false	Read from the processed resources instead of the source resources.
skip	false	Skip execution entirely (maven.yuicompressor.skip).
jswarn	true	Report possible problems found in JavaScript (maven.yuicompressor.jswarn).
failOnWarning	false	Fail the build on warnings. Implies jswarn (maven.yuicompressor.failOnWarning).

compress goal

Parameter	Default	Description
encoding	UTF-8	Character set used to read the input files (file.encoding).
suffix	-min	Suffix appended to the output file name (maven.yuicompressor.suffix).
nosuffix	false	Write the output over the same file name, with no suffix (maven.yuicompressor.nosuffix).
linebreakpos	-1	Insert a line break after the given column. -1 never breaks (maven.yuicompressor.linebreakpos).
force	false	Compress even when the output is newer than the source (maven.yuicompressor.force).
gzip	false	Also write a .gz copy of each compressed file (maven.yuicompressor.gzip).
level	9	GZIP compression level, 0-9 (maven.yuicompressor.level).
statistics	true	Log the compression ratio of each file and the total (maven.yuicompressor.statistics).
useSmallestFile	true	Keep the original when compression makes the file larger (maven.yuicompressor.useSmallestFile).
aggregations	none	Aggregations to run. See File aggregation.
preProcessAggregates	false	Aggregate before compressing instead of after (maven.yuicompressor.preProcessAggregates).

JavaScript-only parameters:

Parameter	Default	Description
nocompress	false	Copy the file without compressing it (maven.yuicompressor.nocompress).
nomunge	false	Minify only; do not obfuscate local symbols (maven.yuicompressor.nomunge).
preserveAllSemiColons	false	Accepted and ignored by YUI Compressor 2.4.11 (maven.yuicompressor.preserveAllSemiColons).
disableOptimizations	false	Accepted and ignored by YUI Compressor 2.4.11 (maven.yuicompressor.disableOptimizations).

Examples

Overwrite the source files

<configuration>
  <nosuffix>true</nosuffix>
</configuration>

Write gzipped copies

<configuration>
  <gzip>true</gzip>
  <level>9</level>
</configuration>

Restrict the files to compress

<configuration>
  <includes>
    <include>**/*.js</include>
  </includes>
  <excludes>
    <exclude>**/vendor/**</exclude>
    <exclude>**/*-min.js</exclude>
  </excludes>
</configuration>

File aggregation

<configuration>
  <aggregations>
    <aggregation>
      <output>${project.build.directory}/${project.build.finalName}/js/all.js</output>
      <includes>
        <include>**/jquery.js</include>
        <include>**/app.js</include>
      </includes>
      <insertNewLine>true</insertNewLine>
    </aggregation>
  </aggregations>
</configuration>

Each aggregation accepts inputDir, output, includes, excludes, removeIncluded, insertNewLine, insertFileHeader, fixLastSemicolon and autoExcludeWildcards. Includes are concatenated in the order they are listed.

JSLint validation

<executions>
  <execution>
    <id>jslint</id>
    <goals>
      <goal>jslint</goal>
    </goals>
  </execution>
</executions>

Migrating from net.alchim31.maven

Change the groupId and version; the artifactId, goals and configuration parameters are unchanged.

<!-- Before -->
<groupId>net.alchim31.maven</groupId>
<artifactId>yuicompressor-maven-plugin</artifactId>
<version>1.5.1</version>

<!-- After -->
<groupId>org.codelibs.maven</groupId>
<artifactId>yuicompressor-maven-plugin</artifactId>
<version>2.0.1</version>

Building from Source

# Build, run unit tests and install into the local repository
mvn clean install

# Unit tests only
mvn test

# Unit and integration tests (src/it, run with maven-invoker-plugin)
mvn verify

# Build without tests
mvn install -DskipTests

Contributing

Bug reports and feature requests belong in the issue tracker. Pull requests are welcome; please make sure mvn verify passes before opening one.

License

Released into the public domain under The Unlicense. See LICENSE.txt.

Credits

• David Bernard - original author
• Piotr Kuczynski - contributor
• Maintained by the CodeLibs Project