nodejs中function*、yield和Promise的示例

var co = require("co");var fs = require("fs");function cusReadFile(fileName) { ???//总之，要返回一个Promise对象，这样写也可以,因为fs.readFile返回的就是一个Promise对象 ???/** ????* return function(fn){ ????* ?fs.readFile(fileName,fn); ????* } ????*/ ???return new Promise(function (resolve, reject) { ???????setTimeout(function () { ???????????resolve("文件内容:abc"); ???????}, 2000); ???});}function* readFile() { ???var a = yield cusReadFile("tem.js"); ???console.log("文件1:" + a); ???var b = yield cusReadFile("index.js"); ???console.log("文件2:" + b);}co(readFile).then(function () { ???console.log("文件读取成功")}).catch(function (err) { ???console.log("错误");});