compiler.initOptions(compilerOptions);
final Result result = compiler.compile(SourceFile.fromCode("externs", ""),
SourceFile.fromReader("source.js", reader), compilerOptions);
if (result.success) {
writer.write(compiler.toSource());
} else {
if (result.errors.length > 0) {
throw new SmallerException("Closure Failed: "
+ result.errors[0].toString());
}