我试图围绕Promises，then，when及其他所有相关内容。我没有太大的成功。这是我用英语想要完成的事情，也许有人可以破解代码，因为到目前为止我没有写过任何作品。
我正在为移动设备编写SPA（单页应用）。基本上所有内容都是一个带有一堆DIV的巨型HTML页面。但是，一次只显示一个DIV。用户将有一个标签栏，可以单击每个图标来显示/隐藏DIV。想想Apple App Store界面，底部有“精选”，“热门排行榜”，“探索”，“搜索”和“更新”。
Businesses AppUrl=example.com的数据库查询
objectId用于查询表Navigation以查找所有导航内容。 “家”，“关于我们”，“菜单”，“活动”，“联系方式”等内容。Module列：
Photos table Pages表Lists表Lists table 基本上就是这样。很简单，但很明显＃4中有嵌套查询。我不知道我是否应该在查询中创建一个巨大的对象然后输出它？或者用它们内部的数组创建一堆不同的对象？真的有点丢失，因为这种语法风格与PHP不同。建议？
这是我的非数据库连接版本：
app.get('/', function(req, res){
var frontpageImages = [
{ caption:"Eggplant, Prosciutto, and Pesto Pressed Sandwiches.", file:"image01.jpg", position:"15%" },
{ caption:"Pico de Gallo", file:"image02.jpg", position:"75%" },
{ caption:"B.L.A.T Croque Madame", file:"image03.jpg", position:"20%" },
{ caption:"Double Oreo Brownie Cupcake", file:"image04.jpg", position:"80%" },
{ caption:"Baked Chicken Chimichangas with Monterey Jack Cheese Sauce", file:"image05.jpg", position:"20%" }
]
var menu = [
{ divider:"Appetizers" },
{ name:"French Fries", picture:"menu-french-fries", subname:"$4.95" },
{ name:"Loaded Cheese Fries", picture:"menu-cheese-fries", subname:"$7.95" },
{ name:"Gaelic Chips", picture:"menu-gaelic-chips", subname:"$2.95" },
{ name:"Jalapeno Mac n' Cheese", picture:"menu-jalapeno-mac-n-cheese", subname:"$4.95" },
{ name:"Chicken Wings", picture:"menu-chicken-wings", subname:"$8.50" },
{ name:"Irish Nachos", picture:"menu-irish-nachos", subname:"$8.50" },
{ name:"Black & Tan Onion Rings", picture:"menu-onion-rings", subname:"$6.95" },
{ name:"Mac's Quesadillas", picture:"menu-quesadillas", subname:"$8.50" },
{ name:"Banger Bites", picture:"menu-banger-bites", subname:"$7.95" },
{ divider:"Salads" },
{ name:"Caesar Salad", picture:"menu-caesar-salad", subname:"$6.50" },
{ name:"House Salad", picture:"menu-house-salad", subname:"$6.50" },
{ name:"Buffalo Chicken Salad (Grilled or Battered)", picture:"menu-buffalo-chicken-salad", subname:"$8.95" },
{ divider:"Sandwiches & Burgers" },
{ name:"Rueben", picture:"menu-reuben", subname:"$8.50" },
{ name:"Dublin Corned Beef", picture:"menu-corned-beef-sandwich", subname:"$8.50" },
{ name:"Philly Cheese Steak", picture:"menu-philly-cheese-steak", subname:"$8.50" },
{ name:"Grilled Chicken", picture:"menu-grilled-chicken-sandwich", subname:"$8.50" },
{ name:"Club Sandwich", picture:"menu-club-sandwich", subname:"$8.50" },
{ name:"Not-So-Irish Burger", picture:"menu-irish-burger", subname:"$9.95" },
{ name:"Dirty Burger", picture:"menu-dirty-burger", subname:"$7.95" },
{ name:"Aurora Burger", picture:"menu-aurora-burger", subname:"$10.95" },
{ name:"Bleu Cheese Burger", picture:"menu-bleu-cheese-burger", subname:"$11.95" },
{ name:"Additional Burger Toppings", picture:"menu-burger-toppings", subname:"$0.50" },
{ divider:"Irish Favorites & Entrees" },
{ name:"Beer Battered Fish N' Chips", picture:"menu-fish-and-chips", subname:"$11.50" },
{ name:"Bangers And Mash", picture:"menu-bangers-and-mash", subname:"$10.95" },
{ name:"Shepherd's Pie", picture:"menu-shepherds-pie", subname:"$10.95" },
{ divider:"Brunch" },
{ name:"Irish Breakfast", picture:"menu-irish-breakfast", subname:"$11.50" },
{ name:"American Breakfast", picture:"menu-american-breakfast", subname:"$11.50" },
{ name:"Irish Breakfast Roll", picture:"menu-irish-breakfast-roll", subname:"$8.95" },
{ name:"English Muffin, Scrambled Eggs, Cheddar and Irish Rasher", picture:"menu-irish-rasher", subname:"$7.50" },
{ name:"3 Egg Omelette", picture:"menu-omelette", subname:"$6.50" },
{ name:"Eggs Benedict", picture:"menu-eggs-benedict", subname:"$8.50" },
{ name:"3 Pancakes with Maple Syrup", picture:"menu-pancakes", subname:"$6.00" },
{ name:"Grilled Turkey and Swiss", picture:"menu-grilled-turkey-and-swiss", subname:"$7.00" }
];
var drinks = [
{ name: "Bahama Bomb", desc: "Bacardi 151 Rum, Cruzan Coconut Rum, Creme de Banana, Pineapple juice, and Sprite.", subname: "$9.95" },
{ name: "Tropical Margarita", desc: "Grand Marnier, Cruzan Coconut Rum, Blue Curacao, sour mix, and orange juice. Garnished with lemon, lime, and cherry.", subname: "$10.95" },
{ name: "LOL[emonade]", desc: "Absolute Citron, Triple Sec, muddled lemon and simple syrup, sour mix, and Sprite.", subname: "$9.95" }
];
var events = [
{ divider:"Upcoming Events" },
{ name: "Super Bowl Party", subname: "1/28" },
{ name: "Valentine's Singles Party", subname: "2/14" },
{ divider:"Weekly Events" },
{ name: "Hospitality Night", subname: "Monday" },
{ name: "Trivia Night", subname: "Tuesday" },
{ name: "Karaoke with Liam", subname: "Thursday" }
];
res.render('index', {
nav:[
{ name:"Home", title:"Clark's Bar and Grille", url:"home", icon:"home", module:"home", run:"startSlider", source:frontpageImages },
{ name:"Menu", url:"menu", icon:"cutlery", module:"list", source:menu },
{ name:"Drinks", url:"drinks", icon:"glass", module:"list", source:drinks },
{ name:"Events", url:"events", icon:"calendar", module:"list", source:events },
{ name:"Restaurant Info", title:"Restaurant Info", url:"business-info", icon:"info-circle", module:"business-info" },
{ name:"Instagram Feed", title:"Instagram", url:"instagram", icon:"instagram", module:"instagram", run:"startInstagram" },
{ name:"Like and Follow Us", title:"Social Media", url:"social-media", icon:"thumbs-up", module:"social-media-links" },
{ name:"Contact Clark's", title:"Contact Clark's", url:"contact", icon:"envelope", module:"contact" }
]
});
}）;
当页面立即渲染时，我让index.ejs循环nav对象并显示每个DIV（Home，Menu，Drinks，Events等）。 nav对象中的每个数组都有一个名为source的键，它返回上面列出的对象。页面渲染完美，它只是没有连接到数据库。我想用DB连接版本交换所有这些！
答案 0 :(得分：1)
我希望此代码可以为您提供帮助，这是我能为您提供的最佳建议：
function handleError(message, error) {
//Handle any error here, for example:
console.error(message, error);
res.send(500, message);
}
var responseContent = {
nav: [],
};
getBusiness(); //start fetching data
function getBusiness() {
var businessQuery = /*query to get element AppUrl=example.com*/;
businessQuery.first().then(
getNavigation,
handleError.bind(null, 'error getting business'));
}
function getNavigations(business) {
var navigationsQuery = /*query to get navigation elements*/;
var promises = [];
navigationsQuery.each(function (navigation) {
promises.push(processNavigation(navigation));
}).then(
function () {
Parse.Promise.when(promises).then(
renderResult,
handleError.bind(null, 'error processing navigations'));
},
handleError.bind(null, 'error iterating navigations'));
}
function processNavigation(navigation) {
var promise = Parse.Promise();
var nav = {
name: /*name*/,
url: /*url*/,
};
responseContent.nav.push(nav);
switch (/*module*/) {
case 'Home':
getPhotosContent(/*args*/).then(
function (source) {
nav.source = source;
promise.resolve();
},
function (error) {
promise.reject(error);
}
);
break;
//can do similar code for 'About Us', 'Menus', ...
default:
promise.resolve();
}
return promise;
}
function getPhotosContent(/*args*/) {
var promise = Parse.Promise();
var results = [];
var photosQuery = /*query to get photos*/;
photosQuery.each(function (photo) {
results.push(photo);
}).then(
function () {
promise.resolve(results);
}, function (error) {
promise.reject(error);
}
);
return promise;
}
function renderResult() {
res.render('index', responseContent);
}