Assert 🔍

A dependency-free, buildless assertion library for node.js and the browser.

Getting Started

At first you need to install the package using the following command:

npm i @kompanie/assert

Usage

The first parameter is usually actual while the second parameter is expected.

Exceptions to this rule are:

• Assert.fail()
• Assert.isNaN(actual)
• Assert.isNotNaN(actual)
• Assert.isBetween(actual, min, max)
• Assert.rejects(fn, expectedErrorType)
• Assert.notRejects(fn, expectedErrorType)
• Assert.throws(fn, expectedErrorType)
• Assert.notThrows(fn, expectedErrorType)
• Assert.isUndefinedOrNull(actual)
• Assert.isNotUndefinedOrNull(actual)

// Equality
Assert.equal(5, 5);
Assert.notEqual(5, 10);

// Deep Equality
Assert.deepEqual({a: 5}, {a: 5});
Assert.notDeepEqual({a: 5}, {a: 10});

// Fail
Assert.fail();

// Includes
Assert.include("Hello World", "Hell");
Assert.include([5, 6, 7], 5);
Assert.notInclude("Hello World", "Foo");
Assert.notInclude([5, 6, 7], 8);

// Instance
Assert.instanceOf(new Date(), Date);
Assert.notInstanceOf({}, Date);

// NaN
Assert.isNaN(NaN);
Assert.isNotNaN(123);

// Number
const tolerance = 0.1;
Assert.approximately(5.01, 5, tolerance);
Assert.isAbove(10, 5);
Assert.isBelow(3, 5);
Assert.isBetween(5, 1, 10);

// Regex
Assert.match("hello123", /hello\d+/u);
Assert.notMatch("hello", /world/u);

// Rejects
const expectedPromiseError = TypeError; // optional
Assert.rejects(async () => { throw new Error(); }, expectedPromiseError);
Assert.notRejects(async () => {}, expectedPromiseError);

// Throws
const expectedErrorType = TypeError; // optional
Assert.throws(() => { throw new Error(); }, expectedErrorType);
Assert.notThrows(() => {}, expectedErrorType);

// Type
Assert.typeOf("hello", "string");
Assert.notTypeOf(123, "string");

// Undefined / Null
Assert.isUndefinedOrNull(null);
Assert.isNotUndefinedOrNull(123);

Tests

This repository includes tests in the tests folder, which can be executed via npm test and opening the browser at localhost:8000