@fantasticfiasco/expect

A Node.js library written in TypeScript providing argument validation.

Table of contents

• Super simple to use
• Installation
• API
• Credit

Super simple to use

import * as expect from '@fantasticfiasco/expect';

function update(person) {
    expect.toExist(person.name);
    expect.toBeTrue(person.age >= 0, 'existential theories are not up for discussion');

    // Squint your eyes and imagine your code here...
}

Installation

npm install @fantasticfiasco/expect
# or
yarn add @fantasticfiasco/expect

API

toBeTrue(condition[, errorMessage])

• condition: boolean The condition expected to be true
• errorMessage: string The optional error message displayed if expectation fails

Expect a condition to be true.

toBeFalse(condition[, errorMessage])

• condition: boolean The condition expected to be false
• errorMessage: string The optional error message displayed if expectation fails

Expect a condition to be false.

toExist<T>(value[, errorMessage])

• value: T The value expected to exist
• errorMessage: string The optional error message displayed if expectation fails

Expect a value to exist.

toNotExist<T>(value[, errorMessage])

• value: T The value expected not to exist
• errorMessage: string The optional error message displayed if expectation fails

Expect a value not to exist.

toBeAlphanumeric(value[, errorMessage])

• value: string The value expected to be alphanumeric
• errorMessage: string The optional error message displayed if expectation fails

Expect a value to be alphanumeric.

toBeCharCodes(value, minCharCode, maxCharCode[, errorMessage])

• value: string The value expected to have characters from a range of character codes
• minCharCode: number The expected minimum character code
• maxCharCode: number The expected maximum character code
• errorMessage: string The optional error message displayed if expectation fails

Expect a value to only contain characters from a range of character codes.

Credit

Thank you JetBrains for your important initiative to support the open source community with free licenses to your products.