NPM Workflow to Preprocess a Javascript File

preprocess-with-esprima-js

var escodegen = require('escodegen')
var through = require('through')
var esprima = require('esprima')
var modify = require('./modify')  // Custom code that you write to preprocess the file

module.exports = function(file, opts) {
  var buffer = []

  return through(function(data) {
    buffer.push(data)
  }, function() {
    buffer = buffer.join('\n')

    var ast = esprima.parse(buffer)

    // Whatever functionality goes here...
    modify(ast)

    buffer = escodegen.generate(ast)
    this.queue(buffer)
    this.queue(null)
  })
}