better-assert

What is better-assert?

The better-assert npm package is a simple assertion library for Node.js. It allows developers to write assertions in their code to ensure that certain conditions hold true. If an assertion fails, it throws an error with a detailed message, making it easier to debug issues.

What are better-assert's main functionalities?

Basic Assertion

This feature allows you to assert that a condition is true. If the condition is false, an error is thrown. In this example, the assertion checks if the variable `x` is equal to 5.

const assert = require('better-assert');
let x = 5;
assert(x === 5);

Assertion with Error Message

This feature allows you to provide a custom error message that will be displayed if the assertion fails. In this example, the assertion checks if the variable `y` is equal to 5, and if not, it throws an error with the message 'y should be 5'.

const assert = require('better-assert');
let y = 10;
assert(y === 5, 'y should be 5');

Complex Assertions

This feature allows you to perform more complex assertions involving multiple conditions. In this example, the assertion checks if the properties `a` and `b` of the object `obj` have the values 1 and 2, respectively.

const assert = require('better-assert');
let obj = { a: 1, b: 2 };
assert(obj.a === 1 && obj.b === 2);

Other packages similar to better-assert

assert

The built-in Node.js 'assert' module provides a set of assertion functions for verifying invariants. It is more feature-rich compared to better-assert, offering a variety of assertion methods such as deepEqual, notEqual, and throws.

chai

Chai is a BDD / TDD assertion library for Node.js and the browser that can be delightfully paired with any JavaScript testing framework. It provides a more expressive and readable syntax compared to better-assert, supporting both 'should', 'expect', and 'assert' styles.

should

Should.js is an expressive, readable, and powerful assertion library for Node.js. It extends the Object prototype with a single non-enumerable property, making it easy to write fluent assertions. It offers more syntactic sugar compared to better-assert.

README

better-assert

Better c-style assertions using callsite for self-documenting failure messages.

Installation

$ npm install better-assert

Example

By default assertions are enabled, however the NO_ASSERT environment variable will deactivate them when truthy.

var assert = require('better-assert');

test();

function test() {
  var user = { name: 'tobi' };
  assert('tobi' == user.name);
  assert('number' == typeof user.age);
}

AssertionError: 'number' == typeof user.age
    at test (/Users/tj/projects/better-assert/example.js:9:3)
    at Object.<anonymous> (/Users/tj/projects/better-assert/example.js:4:1)
    at Module._compile (module.js:449:26)
    at Object.Module._extensions..js (module.js:467:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Module.runMain (module.js:492:10)
    at process.startup.processNextTick.process._tickCallback (node.js:244:9)

License

(The MIT License)

Copyright (c) 2012 TJ Holowaychuk <[e-mail]>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.