Mongoose order of methods

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I am trying to create a new object and saving it to database then find all the objects from database and print it out . but here it's first running the find() method even if i am calling find() method after create(). can anybody explain why is that so?

here is my code :

Cat.create({
    name : "Billy",
    age : 10,
    breed : "Turkish Van"
}, function(err,cat){
    if(err)
        {
            console.log("Oh Error!!");
        }else
            {
                console.log("Great!!");
                console.log(cat); 
                console.log("==========================================");
            }
});

Cat.find({},function(err,cats){
    if(err){
        console.log("Oh Error!!");
    }else {
        console.log("All the cats !!! ");
        console.log(cats);
    }
});

What I have tried:

i tried creting new cat by

var newC=new Cat({
 	name :"Tommy",
 	age : 10,
 	breed: "Persian"
 });

 newC.save(function(err,cat){}

still in console it's running find() method first then create() method. can someone explain why.
Thanks in advance.

Posted 19-Feb-20 23:33pm

Member 14081431

Updated 20-Feb-20 2:48am

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Richard Deeming · Answer 1 · 2020-02-20T02:49:00

The create[^] method returns a promise.

That means the method returns before the insert has completed. It returns an object which will be resolved once the operation has completed.

If you want something to run after the insert has completed, you have a number of options:

Callback:
Move the second operation to the callback function:

JavaScript

Cat.create({
    name : "Billy",
    age : 10,
    breed : "Turkish Van"
}, function(err,cat){
    if(err) {
        console.log("Oh Error!!");
    } else {
        console.log("Great!!");
        console.log(cat); 
        console.log("==========================================");
    }
    
    Cat.find({},function(err,cats){
        if(err) {
            console.log("Oh Error!!");
        } else {
            console.log("All the cats !!! ");
            console.log(cats);
        }
    });
});

Use "then":
Invoke the second operation from the .then callback:

JavaScript

Cat.create({
    name : "Billy",
    age : 10,
    breed : "Turkish Van"
}, function(err,cat){
    if(err) {
        console.log("Oh Error!!");
    } else {
        console.log("Great!!");
        console.log(cat); 
        console.log("==========================================");
    }
}).then(function(){
    Cat.find({}, function(err, cats){
        if(err) {
            console.log("Oh Error!!");
        } else {
            console.log("All the cats !!! ");
            console.log(cats);
        }
    });
});

Use async/await:
Change your code to use async / await:

JavaScript

async function makeACat() {
    try {
        const cat = await Cat.create({
            name : "Billy",
            age : 10,
            breed : "Turkish Van"
        });
        
        console.log("Great!!");
        console.log(cat); 
        console.log("==========================================");
    }
    catch (error) {
        console.error("Oh Error!!", error);
    }
    
    try {
        const cats = await Cat.find({});
        console.log("All the cats !!! ");
        console.log(cats);
    }
    catch (error) {
        console.error("Oh Error!!", error);
    }
}

The 80/20 Guide to Async/Await in Node.js | www.thecodebarbarian.com[^]