User Schema for Mongoose Pre-validation Hook Testing

user-schema.js

var UserSchema = new Schema({
    name: { type: String, required: true },
    username: { type: String, required: true, index: { unique: true } },
    email: String,
    role: {
        type: String,
        default: 'User'
    },
    password: { type: String, required: true }
});