A validate() method will be added to the prototype of structures, this method will validate the structure based on its schema. The method will return an object with the property valid (with the value true if it's valid, and false if invalid). If valid is false the returned object will also have a property errors, with an array of validation errors.

Validations require you to use the complete attribute definition:

const User = attributes({
  name: {
    type: String,
    minLength: 10,
  age: {
    type: Number,
    required: true,
})(class User {});

const user = new User({
  name: 'John',

const { valid, errors } = user.validate();

valid; // false
errors; /*
  { message: '"name" length must be at least 10 characters long', path: ['name'] },
  { message: '"age" is required', path: ['age'] }

const validUser = new User({
  name: 'This is my name',
  age: 25,

const validation = validUser.validate();

validation.valid; // true
validation.errors; // undefined, because `valid` is true

Structure has a set of built-in validations built on top of the awesome joi package:


Validations marked with * accept a value, an attribute reference, or an array of values and attribute references mixed.

Validations marked with ** accept a value or an attribute reference.

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