mongoose TypeError: Schema is not a constructor

I've solved this problem by importing Schema with upper case.

Previous:

const Scheme = mongoose.schema;

After Fixing:

const Schema = mongoose.Schema;

Full Schema:

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const ItemSchema = new Schema({
    name : {
        type: String,
        required : true
    },
    date : {
        type : Date,
        default : Date.Now
    }
});
module.exports = mongoose.model('Item', ItemSchema);

It should be Schema.Types.ObjectId, not Schema.ObjectId: http://mongoosejs.com/docs/schematypes.html

The problem in my case was the export which should (s) at the end:

Problem: missing (s) in exports

module.export = mongoose.model('Event', EventSchema);

Solution: add (s) to exports

module.exports = mongoose.model('Event', EventSchema);

I have encountered the same thing. I have previous code like this

    var mongoose = require('mongoose');
    var Schema = mongoose.Schema();
    var schema = new Schema({
        path : {type:string , required:true},
        title: {type:string , required: true}
    })
 module.export = mongoose.model('game', schema);

Then I solved the constructor problem using below script

   var mongoose = require('mongoose');
    var schema = mongoose.Schema({
        path : {type:string , required:true},
        title: {type:string , required: true}
    })
 module.export = mongoose.model('game', schema);