How do I concatenate multiple files in Gradle?

Question

Is there an easy way to concatenate multiple text files into a single one in Gradle? The build script should look something like this:

FileCollection jsDeps = files(
   'file1.js',
   'file2.js'
   // other files here
)

task concatenate << {
   // concatenate the files to file.js
}

I am using Gradle 2.3.

Answer 1

(new File('test.js')).text = file('test1.js').getText() + file('test2.js').getText()

UPDATE:

For collections.

(new File('test.js')).text = files('test1.js', 'test2.js').collect{it.getText()}.join("\n")