npm package discovery and stats viewer.

Discover Tips

  • General search

    [free text search, go nuts!]

  • Package details

    pkg:[package-name]

  • User packages

    @[username]

Sponsor

Optimize Toolset

I’ve always been into building performant and accessible sites, but lately I’ve been taking it extremely seriously. So much so that I’ve been building a tool to help me optimize and monitor the sites that I build to make sure that I’m making an attempt to offer the best experience to those who visit them. If you’re into performant, accessible and SEO friendly sites, you might like it too! You can check it out at Optimize Toolset.

About

Hi, 👋, I’m Ryan Hefner  and I built this site for me, and you! The goal of this site was to provide an easy way for me to check the stats on my npm packages, both for prioritizing issues and updates, and to give me a little kick in the pants to keep up on stuff.

As I was building it, I realized that I was actually using the tool to build the tool, and figured I might as well put this out there and hopefully others will find it to be a fast and useful way to search and browse npm packages as I have.

If you’re interested in other things I’m working on, follow me on Twitter or check out the open source projects I’ve been publishing on GitHub.

I am also working on a Twitter bot for this site to tweet the most popular, newest, random packages from npm. Please follow that account now and it will start sending out packages soon–ish.

Open Software & Tools

This site wouldn’t be possible without the immense generosity and tireless efforts from the people who make contributions to the world and share their work via open source initiatives. Thank you 🙏

© 2024 – Pkg Stats / Ryan Hefner

assertron

v11.5.2

Published

A supplementary assertion library

Downloads

1,857

Readme

assertron

NPM version NPM downloads

GitHub NodeJS Codecov

Semantic Release

Visual Studio Code

A supplementary assertion library that runs on both NodeJS and browser.

Install

# npm
npm install assertron

# yarn
yarn add assertron

# pnpm
pnpm install assertron

#rush
rush add -p assertron

Usage

assertron provides a collection of assertion methods:

  • assertron.false(value): asserts the provided value is false.
  • assertron.falsy(value): asserts the provided value is falsy.
  • assertron.isInstanceof(value, ClassType): asserts value instanceof ClassType.
  • assertron.pathEqual(actual, expected): asserts the two paths are equal regardless of operating system differences.
  • assertron.rejects(promise): asserts the promise rejects.
  • assertron.repeat(fn, times): repeat the specified function n times and return the last result.
    If the result is a promise, it will run the function sequentially.
  • assertron.resolves(promise): asserts the promise resolves.
  • assertron.satisfies(actual, expected): checks if actual meets the requirements specified by expected.
    Each property in expected can be a value, a RegExp, or a predicate function.
    It uses satisfier internally to check for validity.
    Check out satisfier for more detail.
import a from 'assertron' // assertron is also exported as default.

// these passes
a.satisfies({ a: 1, b: 2 }, { a: 1 })
a.satisfies({ a: 'foo', b: 'boo' }, { a: /foo/ })
a.satisfies({ a: 1, b, 2 }, { a: n => n === 1 })

// these fails
a.satisfies({ a: 1 }, { a: 2 })
a.satisfies({ a: 1 }, { a: 1, b: 2 })
a.satisfies({ a: 'foo' }, { a: /boo/ })
a.satisfies({ a: 1 }, { a: () => false })
  • assertron.throws(...): asserts the promise, function, or async function throws (or rejects) an error.
import { assertron } from 'assertron'

await assertron.throws(Promise.reject(new Error('foo')))
assertron.throws(() => { throw new Error('foo') })
await assertron.throws(() => Promise.reject(new Error('foo')))

const e1 = await assertron.throws(Promise.reject(new SpecificError('foo')), SpecificError)
const e2 = assertron.throws(() => { throw new SpecificError('foo') }, SpecificError)
const e3 = await assertron.throws(() => Promise.reject(new SpecificError('foo')), SpecificError)
  • assertron.true(value): asserts the provided value is true.
  • assertron.truthy(value): asserts the provided value is truthy.

AssertOrder

Assert the code is executed in the expected order.

  • order.once(step: number): asserts the step step executed once.
import { AssertOrder } from 'assertron'

const o = new AssertOrder()
function foo() {
  o.once(1)
}

foo()
foo() // throws
import { AssertOrder } from 'assertron'

const o = new AssertOrder()
function foo() {
  o.once(1)
}

function boo() {
  o.once(2)
}

foo()
boo()
  • order.atLeastOnce(step: number): assert the step executed at least once.
import { AssertOrder } from 'assertron'

const o = new AssertOrder()

for (let i = 0; i < 10; i++)
  o.atLeastOnce(1)


o.once(2)
  • order.exactly(step: number, times: number): asserts the step step executed exactly n times
import { AssertOrder } from 'assertron'

const o = new AssertOrder()

for (let i = 0; i < 4; i++)
  o.exactly(1, 3) // throws at i === 3
  • order.any(steps: number[], handler?: (step: number) => void): asserts any of the steps steps executed.
import { AssertOrder } from 'assertron'

const o = new AssertOrder()

for (let i = 1; i <= 4; i++) {
  if (i % 2)
    o.any([1, 3])
  else
    o.any([2, 4])
}

There are other methods available. Use TypeScript to discover them!

Contribute

yarn

# start making changes
git checkout -b <branch>
yarn watch

# after making change(s)
git commit -m "<commit message>"
git push

# create PR

NPM Commands

There are a few useful commands you can use during development.

yarn test

yarn watch

yarn verify