Structure
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Testing
If you use Jest, Structure has a Jest extension called jest-structure that provides assertions to make it easy to test intances.

Installation

jest-structure is available in npm, so you can install it with npm or yarn as a development dependency:
npm install --save-dev jest-structure
# or
yarn --dev add jest-structure

Setup

After installing, you need to tell Jest to use jest-structure, this can be done in two ways:
By importing and manually adding it to Jest:
import jestStructure from 'jest-structure';
expect.extend(jestStructure);
Or by allowing jest-structure to add itself to Jest matchers:
import 'jest-structure/extend-expect';
Both ways can be done in a setup file or directly at the top of your test file

Matchers

toBeValidStructure()

This matcher passes if the structure is valid:
const User = attributes({
name: { type: String, required: true },
})(class User {});
const validUser = new User({ name: 'Me' });
expect(validUser).toBeValidStructure(); // passes
const invalidUser = new User();
expect(invalidUser).toBeValidStructure(); // fails

toBeInvalidStructure()

This matcher passes if the structure is invalid:
const User = attributes({
name: { type: String, required: true },
})(class User {});
const invalidUser = new User();
expect(invalidUser).toBeInvalidStructure(); // passes
const validUser = new User({ name: 'Me' });
expect(validUser).toBeInvalidStructure(); // fails

toHaveInvalidAttribute(path, messages)

This matcher allows you to assert that a single attribute of the structure is invalid, optionally passing the array of error messages for that attribute:
const User = attributes({
name: { type: String, required: true },
age: { type: Number, required: true },
})(class User {});
const user = new User({ age: 42 });
// passes, because name is invalid
expect(user).toHaveInvalidAttribute(['name']);
// fails, because age is valid
expect(user).toHaveInvalidAttribute(['age']);
// passes, because name is invalid with this message
expect(user).toHaveInvalidAttribute(['name'], ['"name" is required']);
// fails, because name is invalid but not with this message
expect(user).toHaveInvalidAttribute(['name'], ['"name" is not cool']);
// passes. Notice that you can even use arrayContaining to check for a subset of the errros
expect(user).toHaveInvalidAttribute(['name'], expect.arrayContaining(['"name" is required']));
// passes. And stringContaining can be used as well
expect(user).toHaveInvalidAttribute(['name'], [expect.stringContaining('required')]);

toHaveInvalidAttributes([ { path, messages } ])

This matcher allows you to assert that multiple attributes of the structure are invalid, optionally passing the array of error messages for each attribute:
const User = attributes({
name: { type: String, required: true },
age: { type: Number, required: true },
})(class User {});
const user = new User({ age: 42 });
// passes, because name is invalid
expect(user).toHaveInvalidAttributes([{ path: ['name'] }]);
// fails, because age is valid
expect(user).toHaveInvalidAttributes([{ path: ['age'] }]);
// fails, because name is invalid but age is valid
expect(user).toHaveInvalidAttributes([{ path: ['name'] }, { path: ['age'] }]);
// passes, because name is invalid with this message
expect(user).toHaveInvalidAttributes([{ path: ['name'], messages: ['"name" is required'] }]);
// fails, because name is invalid but not with this message
expect(user).toHaveInvalidAttributes([{ path: ['name'], messages: ['"name" is not cool'] }]);
// passes. Notice that you can even use arrayContaining to check for a subset of the errros
expect(user).toHaveInvalidAttributes([
{ path: ['name'], messages: expect.arrayContaining(['"name" is required']) },
]);
// passes. And stringContaining can be used as well
expect(user).toHaveInvalidAttributes([
{ path: ['name'], messages: [expect.stringContaining('required')] },
]);