node中使用promise解决异步问题

fs = require(“fs”); Q = require(“q”);

var test = function() { var defer = Q.defer(); fs.readdir(“d:\test”, function(err, paths) { if (err) defer.reject(err) else defer.resolve(paths); }); return defer.promise; }

var printMessage = function(paths) { var defer = Q.defer(); console.log(“printMessage中打印的paths：”); console.log(paths); defer.resolve(paths); return defer.promise; }

test().then(function(paths) { return printMessage(paths)//需要返回* }).then(function(paths) { console.log(“printMessage函数执行之后打印的paths：”); console.log(paths); });