带有wro4j和谷歌闭包编译器的ECMASCRIPT 5

Question

我们正在使用带有谷歌闭包和Maven的wro4j来缩小我们的JS。默认情况下，它不支持JS中的严格模式("use strict";)..它只是把它去掉了。有没有什么配置可以让我在pom.xml或其他地方把use strict留在那里？

这是google closure编译器的配置：

--language_in=ECMASCRIPT5_STRICT

不知道怎么把它插到Wro4j上。有什么想法吗？

Answer 1

创建添加ECMAScript5的管理器工厂的自定义实现

public class MyCustomWroManagerFactory
extends DefaultStandaloneContextAwareManagerFactory
  {
  @Override 
    protected ProcessorsFactory newProcessorsFactory() 
      {
      final SimpleProcessorsFactory factory = new SimpleProcessorsFactory(); 

      factory.addPreProcessor(
           new GoogleClosureCompressorProcessor(
             CompilerOptions.LanguageMode.ECMASCRIPT5_STRICT
                                               )
                        ); 

      return factory;
      }
  }

在pom.xml中引用它作为wroManagerFactory节点的值：

<configuration>
  <wroManagerFactory>com.mycompany.MyCustomWroManagerFactory</wroManagerFactory>
</configuration>

根据闭包编译器项目的John Lenz的说法，如果您直接使用Compiler API，则应该指定一个CodingConvention。

参考

• GoogleClosureCompressorProcessor.java - method setCompilerOptions
• GoogleClosureCompressorProcessor.java - optionsPool method
• Closure Compiler Service API Reference - language |  Closure Compiler  |  Google Developers

Answer 2

在wro4j-maven-plugin 1.8中，这有点复杂，但也不是那么糟糕。

您需要添加两个Java类。首先覆盖GoogleClosureCompressorProcessor的newCompilerOptions，如下所示：

package com.example.package.wro;

import com.google.javascript.jscomp.CheckLevel;
import com.google.javascript.jscomp.ClosureCodingConvention;
import com.google.javascript.jscomp.CompilerOptions;
import com.google.javascript.jscomp.DiagnosticGroups;
import java.nio.charset.Charset;
import org.apache.commons.lang3.CharEncoding;
import ro.isdc.wro.extensions.processor.js.GoogleClosureCompressorProcessor;

/**
 * Custom processor overriding `newCompilerOptions` to add custom compiler options.
 *
 * Original author: Alex Objelean.
 */
public class CustomGoogleClosureCompressorProcessor extends GoogleClosureCompressorProcessor {

    /**
     * Encoding to use.
     */
    public static final String ENCODING = CharEncoding.UTF_8;

    @Override
    protected CompilerOptions newCompilerOptions() {
        final CompilerOptions options = new CompilerOptions();

        // Set the language_in option on the Google Closure Compiler to prevent errors like:
        // "JSC_TRAILING_COMMA. Parse error. IE8 (and below)"
        options.setLanguageIn(CompilerOptions.LanguageMode.ECMASCRIPT5);

        /**
         * According to John Lenz from the Closure Compiler project, if you are using the Compiler API directly, you should
         * specify a CodingConvention. {@link http://code.google.com/p/wro4j/issues/detail?id=155}
         */
        options.setCodingConvention(new ClosureCodingConvention());
        // use the wro4j encoding by default
        //options.setOutputCharset(Charset.forName(getEncoding()));
        setEncoding(ENCODING);
        options.setOutputCharset(Charset.forName(ENCODING));
        // set it to warning, otherwise compiler will fail
        options.setWarningLevel(DiagnosticGroups.CHECK_VARIABLES, CheckLevel.WARNING);
        return options;
    }
}

您会注意到我注释掉了行getEncoding。这是因为它是私人的。为了以防万一，我还添加了setEncoding。

然后我们需要自定义管理器：

package com.example.package.wro;

import ro.isdc.wro.manager.factory.standalone.DefaultStandaloneContextAwareManagerFactory;
import ro.isdc.wro.model.resource.processor.factory.ProcessorsFactory;
import ro.isdc.wro.model.resource.processor.factory.SimpleProcessorsFactory;

/**
 * Custom manger adding custom processor.
 */
public class CustomWroManagerFactory extends DefaultStandaloneContextAwareManagerFactory {

    @Override
    protected ProcessorsFactory newProcessorsFactory() {
        final SimpleProcessorsFactory factory = new SimpleProcessorsFactory();

        factory.addPreProcessor(
            new CustomGoogleClosureCompressorProcessor()
        );

        return factory;
    }
}

然后在wroManagerFactory中的pom.xml中使用它。大概是这样的：

        <plugin>
            <groupId>ro.isdc.wro4j</groupId>
            <artifactId>wro4j-maven-plugin</artifactId>
            <version>1.8.0</version>
            <executions>
                <execution>
                    <phase>compile</phase>
                    <goals>
                        <goal>run</goal>
                    </goals>
                </execution>
            </executions>
            <!-- Google Closure Compiler -->
            <!-- http://www.gzfs020.com/using-google-closure-compiler-with-wro4j-maven-plugin.html -->
            <configuration>
                <contextFolder>${basedir}/src/main</contextFolder>
                <wroFile>${basedir}/src/main/config/wro.xml</wroFile>
                <destinationFolder>${project.build.directory}/${project.build.finalName}/min</destinationFolder>
                <!--
                <wroManagerFactory>ro.isdc.wro.extensions.manager.standalone.GoogleStandaloneManagerFactory</wroManagerFactory>
                -->
                <wroManagerFactory>com.example.package.wro.CustomWroManagerFactory</wroManagerFactory>
            </configuration>
        </plugin>