userschema data validation

var mongoose = require('mongoose');
var uniqueValidator = require('mongoose-unique-validator');

// schema representing user data
var UserSchema = new mongoose.Schema(
  {
    username: {
      type: String,
      lowercase: true,
      unique: true,
      required: [true, "can't be blank"],
      match: [/^[a-zA-Z0-9]+$/, 'is invalid'],
      index: true,
    },
    email: {
      type: String,
      lowercase: true,
      unique: true,
      required: [true, "can't be blank"],
      match: [/\S+@\S+\.\S+/, 'is invalid'],
      index: true,
    },
    bio: String,
    image: String,
    hash: String,
    salt: String,
  },
  {timestamps: true}
);

UserSchema.plugin(uniqueValidator, {message: 'is already taken.'});

// register the schema with mongoose as 'User'
mongoose.model('User', UserSchema);