index.js
function convertToJson(callback) {
    var output = new File(file);
    output.contents = new Buffer(JSON.stringify(spritesheet, null, '\t'));
    output.path = file;
    this.push(output);
    callback();
  }
function convertToJson(callback) {
    var output = new File(file);
    output.contents = new Buffer(JSON.stringify(spritesheet, null, '\t'));
    output.path = file;
    this.push(output);
    callback();
  }
function convertToJson ( callback ) { var output = new File ( file ) ; output . contents = new Buffer ( JSON . stringify ( spritesheet , null , '\t' ) ) ; output . path = file ; this . push ( output ) ; callback ( ) ; }
Once all files have been compressed, return compressed JSON file.
@param {Function} callback
Once all files have been compressed return compressed JSON file .