Enforce: The Assertion Library for Vest

Enforce is a powerful assertion library used in the Vest validation framework to validate and enforce certain conditions on input data. With its intuitive API and fluent syntax, Enforce makes it easy to perform data validation and ensure that your code is robust and error-free.

How to Use Enforce

Enforce is used within a Vest test, and can be imported alongside the test function from the vest package:

import { enforce, test } from 'vest';

Once imported, you can use enforce to perform assertions on your input data. Here's a basic example that checks whether a username string is longer than 2 characters:

test('username', 'Must be at least three characters long', () => {
  enforce(username).longerThan(2);
});

In this example, the enforce function is called with the username variable as input data, and the longerThan assertion is chained onto the function call with the value 2 passed as an argument. If the username string is shorter than 3 characters, the assertion will fail and an error will be thrown.

Fluent Chaining API

Enforce provides a fluent chaining API that allows you to chain multiple assertions together and test various conditions on your input data. Here's an example that checks whether a number is greater than 2:

enforce(4).isNumber().greaterThan(2);

In this example, the enforce function is called with the number 4 as input data. The isNumber assertion is first chained onto the function call to check that the input is a number, and then the greaterThan assertion is chained on to check whether the input number is greater than 2. If either of these assertions fails, an error will be thrown.