如何正确地构造一个循环,以确保下面的promise call和链接的logger.log(res)在迭代中同步运行?(蓝鸟)
db.getUser(email).then(function(res) { logger.log(res); }); // this is a promise
我try 了以下方法(从http://blog.victorquinn.com/javascript-promise-while-loop开始)
var Promise = require('bluebird');
var promiseWhile = function(condition, action) {
var resolver = Promise.defer();
var loop = function() {
if (!condition()) return resolver.resolve();
return Promise.cast(action())
.then(loop)
.catch(resolver.reject);
};
process.nextTick(loop);
return resolver.promise;
});
var count = 0;
promiseWhile(function() {
return count < 10;
}, function() {
return new Promise(function(resolve, reject) {
db.getUser(email)
.then(function(res) {
logger.log(res);
count++;
resolve();
});
});
}).then(function() {
console.log('all done');
});
虽然它似乎有效,但我认为它不能保证拨打logger.log(res);的顺序
有什么建议吗?