JarCastingConcat with source maps 
NPM module for concatenating files and generating source maps.
Usage example
var concat = new Concat(true, 'all.js', '\n');
concat.add(null, "// (c) John Doe");
concat.add('file1.js', file1Content);
concat.add('file2.js', file2Content, file2SourceMap);
var concatenatedContent = concat.content;
var sourceMapForContent = concat.sourceMap;
API
new Concat(generateSourceMap, outFileName, separator)
Initialize a new concat object.
Parameters:
- generateSourceMap: whether or not to generate a source map (default: false)
- outFileName: the file name/path of the output file (for the source map)
- separator: the string that should separate files (default: no separator)
concat.add(fileName, content, sourceMap)
Add a file to the output file.
Parameters:
- fileName: file name of the input file (can be null for content without a file reference, e.g. a license comment)
- content: content (Buffer or string) of the input file
- sourceMap: optional source map of the input file (string). Will be merged into the output source map.
concat.content
The resulting concatenated file content (Buffer).
concat.sourceMap
The resulting source map of the concatenated files (string).