Slugger

Description

Slugger is a lightweight TypeScript base class that provides common test utilities - random slug generation, assign-once properties, auto-generated created and updated timestamps, and error helpers. It is designed to be extended by child classes for more specialized testing scenarios.

Installation

npm install --save-dev @nuov.io/slugger

Usage

import { Slugger } from "@nuov.io/slugger";

const slugger = new Slugger();

// Generate a random 10-character alphanumeric slug
const slug = slugger.generateSlug(); // e.g. "aB3xK9mQ2z"

// Access the persistent primary slug (stable for the instance lifetime)
const id = slugger.primarySlug; // e.g. "pL7wR4nT1c"

// Generate errors with slug-based messages
const error = slugger.generateError(true); // Error("pL7wR4nT1c")

// Assign-once properties (throw if reassigned to a different value)
slugger.assignedValue = "some-value";
slugger.assignedValue = "other-value"; // throws Error

// Auto-generated created/updated timestamps
console.log(slugger.created); // Date (older)
console.log(slugger.updated); // Date (newer)

// Reset all state between tests
slugger.beforeEach();

Using in a test suite

import { Slugger } from "@nuov.io/slugger";

const slugger = new Slugger();

beforeEach(() => {
  slugger.beforeEach();
});

it("should generate unique slugs for tests", () => {
  const a = slugger.generateSlug();
  const b = slugger.generateSlug();
  expect(a).not.toEqual(b);
  expect(a.length).toEqual(10);
});

API Reference

Properties

| Property | Type | Description | | ---------------- | --------------------- | ---------------------------------------------- | | assignedValues | Array<unknown> | Array for collecting multiple assigned values. | | error | Error \| undefined | A general-purpose error slot. | | sentence | string \| undefined | A sentence string, used by sentenceError. | | value | string \| undefined | A general purpose value slot. |

Getters

| Method | Returns | Description | | ------------------ | -------------------- | --------------------------------------------------------------------------------------------------------------- | | assignedError | Error \| undefined | The assigned error, or undefined if not yet assigned. | | assignedValue | unknown | The assigned value, or undefined if not yet assigned. | | created | Date | Auto-generated creation timestamp (1 min - 1 hr before updated). | | faker | Faker | The Faker instance. | | handledError | Error \| undefined | The handled error, or undefined if not yet assigned. | | handledValue | unknown | The handled value, or undefined if not yet assigned. | | primarySlug | string | The persistent 10-character slug. This is generated on construction and regenerated by the beforeEach() method. | | sentenceError | Error | Creates an Error from the sentence property. Throws if sentence is undefined. | | theQuickBrownFox | string | Returns "The quick brown fox jumped over the lazy dog." | | updated | Date | Auto-generated update timestamp (1 hr - 1 wk in the past). |

Setters (assign-once)

The following setters enforce assign-once semantics - setting a value a second time with a different value throws an Error.

| Setter | Type | Throws on reassignment | | --------------- | -------------------- | ----------------------------------------------------- | | assignedError | Error \| undefined | "The property 'assignedError' is already assigned." | | assignedValue | unknown | "The property 'assignedValue' is already assigned." | | handledError | Error \| undefined | "The property 'handledError' is already assigned." | | handledValue | unknown | "The property 'handledValue' is already assigned." |

Generation Methods

| Method | Returns | Description | | ------------------------------------------- | -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | generateSlug(isPrimary?: boolean) | string | Generates a random 10-character alphanumeric string. Pass true to return the stable primarySlug. | | generateError(isPrimary?: boolean) | Error | Creates an Error whose message is a generated slug (or the primarySlug when isPrimary is true). | | generateErrorHandler(isPrimary?: boolean) | ErrorHandler | Creates an ErrorHandler that assigns a generated error to handledError on execution. The generated Error message is a generated slug (or the primarySlug when isPrimary is true). |

Other Methods

| Method | Returns | Description | | -------------- | ------- | ----------------------------------------------------------------------------------------- | | beforeEach() | void | Resets all state - slugs, errors, values, dates, and sentence - for clean test isolation. |

License

MIT License

Credits

None of this would have been possible without Faker as a starting point.