How can you remove all documents from a collection with Mongoose?

DateTime.remove({}, callback) The empty object will match all of them.

.remove() is deprecated. instead we can use deleteMany

DateTime.deleteMany({}, callback).

In MongoDB, the db.collection.remove() method removes documents from a collection. You can remove all documents from a collection, remove all documents that match a condition, or limit the operation to remove just a single document.

Source: Mongodb.

If you are using mongo sheel, just do:

db.Datetime.remove({})

In your case, you need:

You didn't show me the delete button, so this button is just an example:

<a class="button__delete"></a>

Change the controller to:

exports.destroy = function(req, res, next) {
    Datetime.remove({}, function(err) {
            if (err) {
                console.log(err)
            } else {
                res.end('success');
            }
        }
    );
};

Insert this ajax delete method in your client js file:

        $(document).ready(function(){
            $('.button__delete').click(function() {
                var dataId = $(this).attr('data-id');

                if (confirm("are u sure?")) {
                    $.ajax({
                        type: 'DELETE',
                        url: '/',
                        success: function(response) {
                            if (response == 'error') {
                                console.log('Err!');
                            }
                            else {
                                alert('Success');
                                location.reload();
                            }
                        }
                    });
                } else {
                    alert('Canceled!');
                }
            });
        });

MongoDB shell version v4.2.6
Node v14.2.0

Assuming you have a Tour Model: tourModel.js

const mongoose = require('mongoose');

const tourSchema = new mongoose.Schema({
  name: {
    type: String,
    required: [true, 'A tour must have a name'],
    unique: true,
    trim: true,
  },
  createdAt: {
    type: Date,
    default: Date.now(),
  },
});
const Tour = mongoose.model('Tour', tourSchema);

module.exports = Tour;

Now you want to delete all tours at once from your MongoDB, I also providing connection code to connect with the remote cluster. I used deleteMany(), if you do not pass any args to deleteMany(), then it will delete all the documents in Tour collection.

const mongoose = require('mongoose');
const Tour = require('./../../models/tourModel');
const conStr = 'mongodb+srv://lord:<PASSWORD>@cluster0-eeev8.mongodb.net/tour-guide?retryWrites=true&w=majority';
const DB = conStr.replace('<PASSWORD>','ADUSsaZEKESKZX');
mongoose.connect(DB, {
    useNewUrlParser: true,
    useCreateIndex: true,
    useFindAndModify: false,
    useUnifiedTopology: true,
  })
  .then((con) => {
    console.log(`DB connection successful ${con.path}`);
  });

const deleteAllData = async () => {
  try {
    await Tour.deleteMany();
    console.log('All Data successfully deleted');
  } catch (err) {
    console.log(err);
  }
};