types-guards

Small, focused utilities for runtime type checks and safe value coercions in TypeScript/JavaScript.

Features

• Lightweight guards: isString, isNumber, isBoolean, isNull, isArray, isFunction, isUndefined, isNullish.
• Empty checks: isEmptyString, isEmptyArray.
• Ensure helpers that coerce or return safe defaults: ensureString, ensureNumber, ensureBoolean, ensureArray, ensureNull, ensureUndefined.

Table of Contents

• Install
• Quick Usage
• Utilities
  • Check types
  • Check empty values
  • Ensure values
• License

Install

Install with your package manager of choice:

pnpm add types-guards
# or
npm install types-guards
# or
yarn add types-guards

Quick Usage

import { isString, isEmptyArray, ensureString, ensureArray } from 'types-guards'

if (isString(value)) {
  // value is narrowed to string
}

const s = ensureString(maybeValue) // returns a string or ''
const arr = ensureArray(maybeList) // returns an array or []

Utilities

Check types

| Function | Description | | --------------- | ----------------------------------------------- | | isString() | Determines whether a value is a string | | isNumber() | Determines whether a value is a number | | isBoolean() | Determines whether a value is a boolean | | isNull() | Determines whether a value is null | | isArray() | Determines whether a value is an array | | isFunction() | Determines whether a value is a function | | isUndefined() | Determines whether a value is undefined | | isNullish() | Determines whether a value is undefined or null |

Check empty values

| Function | Description | | ----------------- | --------------------------------------------- | | isEmptyString() | Determines whether a value is an empty string | | isEmptyArray() | Determines whether a value is an empty array |

Ensure values

| Function | Description | | ------------------- | -------------------------------------------------------------------------------------------- | | ensureString() | Determines whether a value is a string and returns it, otherwise returns an empty string | | ensureBoolean() | Determines whether a value is a boolean and returns it, otherwise returns a false value | | ensureNumber() | Determines whether a value is a number and returns it, otherwise returns a zero value | | ensureUndefined() | Determines whether a value is undefined and returns it, otherwise returns an undefined value | | ensureNull() | Determines whether a value is null and returns it, otherwise returns a null value | | ensureArray() | Determines whether a value is an array and returns it, otherwise returns an empty array |

License

MIT License

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