gulp function to write jade variables to a json file

gulpWriteToJson.js

var through = require('through2');
var matter = require('jade-var-matter');
var jsonfile = require('jsonfile')

// Example -- sending jade files to writeToJson function
gulp.task('postsmeta', function() {
  return gulp.src( jadesrc +'posts/*')
    .pipe(writeToJson(
      dest = jadesrc +'pages/data.json' // set file path
    ))
})

function writeToJson (dest) {
  // USAGE: pipes the jade source files in -- these files should have variables in the front matter
  // example -var name:  "Little Engine", desc: "I am a post"
  // Plugins jade-var-matter, jsonfile, through2
  // Optional: "dest" -- sets file path output --> otherwise a data.json is placed at the root
  // example:  dest = jadesrc +'pages/data.json'
  if (!dest) {
    dest = './data.json'
  }
  // delete current list (so we won't get duplicates)
    del(dest)
  
  return through.obj(function(file, enc, cb){
    // read jade variables into an object (uses plugin jade-var-matter )
    var obj = matter(file.contents.toString());
    // append the items to the destination Json file (used the plugin jsonfile)
   jsonfile.writeFile(dest, obj, {flag: 'a'}, function (err) {
     if (err) throw err;
   })
    cb(null);
  });
}

// Note: Json file is not in the correct format for reading multiple level arrays (like with multiple post)
// check gist postToJson