refreshToken.js

const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const libs = `${process.cwd()}/libs`;
const User = require(`${libs}/models/user`);

let RefreshToken = new Schema({
    userId: {
        type: Schema.Types.ObjectId,
        required: true,
        ref: 'User'
    },
    token: {
        type: String,
        unique: true,
        required: true
    },
    createdAt: {
        type: Date,
        default: Date.now
    }
});

module.exports = mongoose.model('RefreshToken', RefreshToken);