## 指定成功和失败的回调 ``` const fs = require('fs') const path = require('path') var promise = new Promise(function (resolve, reject) { fs.readFile(path.join(__dirname, './11.txt'), 'utf-8', (err, data) => { if (err) return reject(err); resolve(data); }); }); promise.then(function (data) { console.log(data); }, function (error) { console.log(error.message); }); ```