Node js , mongo DB get data from multiple collections using async

Question

Hello im trying to get all my blogs from DB and change the author name from another collection from the database then rendering them to ejs file however the page renders before the array is filled up

app.get('/', async (req, res) => {
      let blogList = new Array(); 
      await Blog.find({}, function (err, foundBlog) { 
        console.log(foundBlog);
        if (err) {
          console.log(err);
        } else {
          foundBlog.forEach(async (blog) => {
            await Author.findById(blog.author, async (err, author) => {
              if (err) {
                console.log(err);
              } else {
                blog.author = author.name;
                console.log('this is the blogs' + blog);
                blogList.push(blog);
                console.log('array length 1 is ' + blogList.length);
              }
            });
          });
          console.log('array length 2 is ' + blogList.length);
          console.log(blogList);
          res.render('home', { blogs: blogList });
        }
      });
    });

Try replacing your code with this code

Yousaf
– Yousaf

2022-03-01 10:09:36 +00:00
Commented Mar 1, 2022 at 10:09 — Yousaf
– Yousaf, Commented Mar 1, 2022 at 10:09

Asad Haroon · Accepted Answer · 2022-03-01 10:22:54Z

1

Please use ref of Author in Blog. In other words make a relation of blog with author. And then your backend should be as follows:

app.get('/', async (req, res) => {
      
         const blogs=await Blog.find({}).populate('author').exec(); // field name author is being populated.
      
          res.render('home', { blogs });
        }
    
    );

const BlogSchema=new mongoose.Schema({
 ... rest of fields,
 author:{
  type:ObjectId,
  ref:"Author" // here it is model name 
 }
});

With this code now your whole author object will be embedded in each blog like:

blog={
  name:"",
  author:{
    name:"Abc",
  }
}

And you can easily get author details by accessing blog.author.name.

edited Mar 1, 2022 at 10:22

answered Mar 1, 2022 at 10:14

Asad Haroon

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2 Comments

Yousaf Over a year ago

Note to OP: this is the better approach as compared to what you are doing. Author document should be nested inside the blog document. This way, you don't need to query the Author collection. In fact, you can just get rid of the Author collection.

Codz Boltz Over a year ago

so ill nest the author object inside the blog collection... thank you sir for the help !

RONAK SUTARIYA · Accepted Answer · 2022-03-08 13:07:34Z

0

for your query, you can explore populate in your Mongo Schema in the collection.

const BlogSchema = new mongoose.Schema({
 author:{
  type:ObjectId,
  ref:"Author" //here it is model name 
 }
})
const Blog = mongoose.model("Blog", BlogSchema )

const AutherSchema = new mongoose.Schema({
 _id:{
  type:ObjectId
 }
})
const Auther = mongoose.model("Auther", AutherSchema)

 app.get('/', async (req, res) => {
      
 const blogs = await Blog.find({}).populate('author').exec(); // field name author is being populated.
         res.send(blogs)
        }
    )

answered Mar 8, 2022 at 13:07

RONAK SUTARIYA

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