assertron

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.

importafrom'assertron'// assertron is also exported as default.// these passesa.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 failsa.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'awaitassertron.throws(Promise.reject(newError('foo')))assertron.throws(()=>{thrownewError('foo')})awaitassertron.throws(()=>Promise.reject(newError('foo')))conste1=awaitassertron.throws(Promise.reject(newSpecificError('foo')),SpecificError)conste2=assertron.throws(()=>{thrownewSpecificError('foo')},SpecificError)conste3=awaitassertron.throws(()=>Promise.reject(newSpecificError('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'consto=newAssertOrder()functionfoo(){o.once(1)}foo()foo()// throws

import{AssertOrder}from'assertron'consto=newAssertOrder()functionfoo(){o.once(1)}functionboo(){o.once(2)}foo()boo()

• order.atLeastOnce(step: number): assert the step executed at least once.

import{AssertOrder}from'assertron'consto=newAssertOrder()for(leti=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'consto=newAssertOrder()for(leti=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'consto=newAssertOrder()for(leti=1;i<=4;i++){if(i%2)o.any([1,3])elseo.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