learn Q

node&Q

var Q = require('./q.js');
var FS = require('fs');

// 方法1 defer
var deferred = Q.defer();
FS.readFile("url.js", "utf-8", function (error, text) {
    if (error) {
        deferred.reject(new Error(error));
    } else {
        deferred.resolve(text);
    }
});

deferred.promise
.then(function(text) {
	console.log('Success: ' + text);
}, function(reason) {
	console.log('Failed: ' + reason);
}, function(notice) {
	console.log('Got notification: ' + notice);
})
.then(function(){
	console.log("1");
}).then(function(){
	console.log("2");
});

// 方法2 nfcall
Q.nfcall(FS.readFile, "helloworld.js", "utf-8")
.then(function(filec){
	console.log("content:" + filec);
},function(reason){
	console.log(reason);
});

// 方法3 从node中构造promise
// return Q.ninvoke(redisClient, "get", "user:1:id");
// return Q.npost(redisClient, "get", ["user:1:id"]);

var readFile = Q.denodeify(FS.readFile);
readFile("exists.txt", "utf-8")
.then(function(result){
	console.log("noerr:" + result);
},function(reason){
	console.log("err:" + reason);
});

// var redisClientGet = Q.nbind(redisClient.get, redisClient);
// return redisClientGet("user:1:id");

// var deferred = Q.defer();
// FS.readFile("foo.txt", "utf-8", deferred.makeNodeResolver());
// return deferred.promise;