'Mongoose: Get full list of users
I have tried to use Mongoose to send the list of all users as follows:
server.get('/usersList', function(req, res) {
var users = {};
User.find({}, function (err, user) {
users[user._id] = user;
});
res.send(users);
});
Of course, res.send(users); is going to send {}, which is not what I want. Is there a find alternative with slightly different semantics, where I could do the following?
server.get('/usersList', function(req, res) {
User.find({}, function (err, users) {
res.send(users);
});
});
Essentially, I want the callback to be executed only when all the users have been fetched from the database.
Solution 1:[1]
Well, if you really want to return a mapping from _id to user, you could always do:
server.get('/usersList', function(req, res) {
User.find({}, function(err, users) {
var userMap = {};
users.forEach(function(user) {
userMap[user._id] = user;
});
res.send(userMap);
});
});
find() returns all matching documents in an array, so your last code snipped sends that array to the client.
Solution 2:[2]
If you'd like to send the data to a view pass the following in.
server.get('/usersList', function(req, res) {
User.find({}, function(err, users) {
res.render('/usersList', {users: users});
});
});
Inside your view you can loop through the data using the variable users
Solution 3:[3]
There was the very easy way to list your data :
server.get('/userlist' , function (req , res) {
User.find({}).then(function (users) {
res.send(users);
});
});
Solution 4:[4]
This is just an Improvement of @soulcheck 's answer, and fix of the typo in forEach (missing closing bracket);
server.get('/usersList', (req, res) =>
User.find({}, (err, users) =>
res.send(users.reduce((userMap, item) => {
userMap[item.id] = item
return userMap
}, {}));
);
);
cheers!
Solution 5:[5]
Same can be done with async await and arrow function
server.get('/usersList', async (req, res) => {
const users = await User.find({});
const userMap = {};
users.forEach((user) => {
userMap[user._id] = user;
});
res.send(userMap);
});
Solution 6:[6]
In case we want to list all documents in Mongoose collection after update or delete
We can edit the function to some thing like this:
exports.product_update = function (req, res, next) {
Product.findByIdAndUpdate(req.params.id, {$set: req.body}, function (err, product) {
if (err) return next(err);
Product.find({}).then(function (products) {
res.send(products);
});
//res.send('Product udpated.');
});
};
This will list all documents on success instead of just showing success message
Solution 7:[7]
To make function to wait for list to be fetched.
getArrayOfData() {
return DataModel.find({}).then(function (storedDataArray) {
return storedDataArray;
}).catch(function(err){
if (err) {
throw new Error(err.message);
}
});
}
Solution 8:[8]
My Solution
User.find()
.exec()
.then(users => {
const response = {
count: users.length,
users: users.map(user => {
return {
_id: user._id,
// other property
}
})
};
res.status(200).json(response);
}).catch(err => {
console.log(err);
res.status(500).json({
success: false
})
})
Solution 9:[9]
You can try this -
User.find().exec(function(err, users){
console.log('users : ', users);
console.log('err', err);
return res.send(users);
});
Solution 10:[10]
The callback method is only executed once the query has been performed.
app.get('/api/users', (req,res) => {
User.find({}, (err, users) => err ? console.log(err) : res.json(users));
});
Solution 11:[11]
you can also do it by async function to get all the users
await User.find({},(err,users)=>{
if (err){
return res.status(422).send(err)
}
if (!users){
return res.status(422).send({error:"No data in the collection"})
}
res.send({Allusers:users})
})
Sources
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Source: Stack Overflow