$ mkdir es6_quiz && cd es6_quiz $ npm init $ npm install acorn espurify concat-stream var acorn = require('acorn'); var espurify = require('espurify'); var concat = require('concat-stream'); var parserOptions = { ecmaVersion: 6 }; process.stdin.pipe(concat(function (buf) { var jsCode = buf.toString('utf-8'); var ast = acorn.parse(jsCode, parserOptions); console.log(JSON.stringify(espurify(ast), nu