http-assert-plus

More assertions with status codes.

import assert from 'http-assert-plus';
// or
const assert = require('http-assert-plus');

const username = 'jdrydn';
assert(username === 'not-jdrydn', 403, 'Authorization failed', {
  code: 'NOT_AUTHORIZED',
  username,
});

// Error: Authorization failed
//     at http-assert-plus/README.md:22:1 {
//   code: 'NOT_AUTHORIZED',
//   statusCode: 403,
//   status: 403,
//   statusText: 'Forbidden',
//   username: 'jdrydn'
// }

Install

$ npm install --save http-assert-plus

API

This API matches the built-in assert module, and builds upon the success of http-assert, with a few differences:

• Each function throws an instance of Error when the assertion fails.
• Zero dependencies.

assert(value, [status], [message], [props])

Tests if value is truthy, and throws an Error if falsey.

assert.ok(value, [status], [message], [props])

Alias for above, tests if value is truthy, and throws an Error if falsey.

assert.fail([status], [message], [props])

Always throws an Error with the provided status/message/props.

assert.equal(a, b, [status], [message], [props])

Tests shallow, coercive equality between a & b using ==.

assert.notEqual(a, b, [status], [message], [props])

Tests shallow, coercive inequality between a & b using !=.

assert.strictEqual(a, b, [status], [message], [props])

Tests strict equality between a & b using ===.

assert.notStrictEqual(a, b, [status], [message], [props])

Tests strict inequality between a & b using !==.

assert.includes(a, b, [status], [message], [props])

Tests whether a includes b - where a has a method call includes.

assert.notIncludes(a, b, [status], [message], [props])

Tests whether a does not include b - where a has a method includes.

What about deep equality?

If you're looking for deep equality checks, check out deep-equal:

import assert from 'http-assert-plus';
import deepEqual from 'deep-equal';

assert(deepEqual(a, b), 400, 'These two are not entirely equal');
assert(deepEqual(a, b, { strict: true }), 400, 'These two are not entirely equal');
// Error: Array does not strict-equal
//     at http-assert-plus/README.md:72:1 {
//   statusCode: 400,
//   status: 400,
//   statusText: 'Bad Request'
// }

Browser supported?

Yes! Not all browsers support Error.captureStackTrace so this library checks if it is present in the current environment - if it isn't available the only behaviour you'll likely want to change is to pre-construct Error arguments to preserve a proper stack trace, like so:

const { origin } = window.location;

// In browsers, do this:
assert(origin.startsWith('https://'), new Error('Expected origin to start with https://'), { origin });
// Error: Expected origin to start with https://
//     at http-assert-plus/README.md:99:39 {
//   origin: 'http://localhost:4000',
// }

// Not this
assert(origin.startsWith('https://'), 'Expected origin to start with https://');
// Error: Expected origin to start with https://
//     at node_modules/http-assert-plus/index.cjs:56:38 {
//     at http-assert-plus/README.md:107:1 {
//   origin: 'http://localhost:4000',
// }

If you don't use a construct such as new Error, when reading stacktraces just ignore the first line as it'll always be the assert function 😉