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求代码优化建议(异步)

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初学node,很不适应这种异步的编码方式,以下是一个简单的route,获取三份数据,分别是:

  1. 文章目录
  2. 首要文章
  3. 最近文章

其中1,2无关联,随意执行,3是要2加载后,才能加载。 所以我用到3个promise,1,2并一起一个,3一个,整个代码下来,我觉得好丑。 不知道你们怎么写的?

var _ = require("lodash");
var express = require('express');
var router = express.Router();
const helper = require("../lib/helper");
const Category = require("../models/categories");
const Article = require("../models/articles");
const viewHelper = require("../lib/viewHelper");


var cateDb = new Category();
var articleDb = new Article();
var topArticleCount = 2;



function findCates() {
  return new Promise(function (resolve, reject) {
    cateDb.findAll(function (items) {
      console.log("cate count:" + items.length);
      resolve(items);
    });
  });
}

function findArticles() {
  return new Promise(function (resolve, reject) {
    articleDb.findTop(2, function (results) {
      resolve(results);
    });
  });
}

/**
 * 最近文章
 */
function findNewArticles(excludeIDs) {
  return new Promise(function (resolve, reject) {
    articleDb.find({ size: 3 + topArticleCount, index: 1 }, function (docs) {
      _.remove(docs, item => {
        return excludeIDs.includes(item._id.toString());
      });
      resolve(docs);
    });
  });
}

/* GET home page. */
router.get('/', function (req, res, next) {
  let cates, articles; // 目录,首要文章
  let newArticles; // 叫近文章
  let p1 = findCates();
  let p2 = findArticles();
  let promise = Promise.all([p1, p2]);
  promise.then(function (items) {
    // 以下两行代码其丑无比,不能直观的知道 items[0], items[1]是什么东西
    cates = items[0]; 
    articles = items[1];

    //  获取最近文件列表
    let excludeIDs = articles.map(item => item._id.toString());
    findNewArticles(excludeIDs).then(function (result) {
      newArticles = result;
      render();
    }).catch(function (err) {
      throw err;
    });
  }).catch(function (err) {
    throw err;
  });

  let render = function () {
    console.log("index rendering...");

    helper.formatDateTime(articles, { "createdTime": "YYYY/MM-DD" });
    helper.formatDateTime(newArticles, { "createdTime": "YYYY/MM-DD" });
    viewHelper.registerByName("_blog_summary")
    viewHelper.registerByName("_article_item");
    res.renderX('index', {
      cates,
      articles,
      newArticles,
      title: 'Express',
    });
  };



});

module.exports = router;


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