promise
封装Promise
var fs = require('fs') function pReadFile(filePath) { return new Promise(function (resolve, reject) { fs.readFile(filePath, 'utf8', function (err, data) { if (err) { reject(err) } else { resolve(data) } }) }) } pReadFile('./data/a.txt') .then(function (data) { console.log(data) return pReadFile('./data/b.txt') }) .then(function (data) { console.log(data) return pReadFile('./data/c.txt') }) .then(function (data) { console.log(data) })