text: // parse.js
  const recast = require('recast')
  
  const code = `function add (a, b) {
  return a+b
  }`
  
  const ast = recast.parse(code)
  
  // 获取代码块 ast 的第一个 body，即我们的 add 函数
  const [add] = ast.program.body
  
  console.log(add)
  
  console.log(recast.print(ast).code)
  console.log(recast.prettyPrint(ast, { tabWidth: 2 }).code)
  