@analytics/type-utils/README.md

Tiny runtime type checking utils

<!--
title: Javascript type utils
pageTitle: Type utils
description: Utility library for runtime type checking
-->

# Type Utilities

A tiny tree shakable utility library for runtime type checking.

The entire package weighs in at <!-- AUTO-GENERATED-CONTENT:START (pkgSize) -->`2.23kb`<!-- AUTO-GENERATED-CONTENT:END -->.

[See live demo](https://utils-types.netlify.app/).

### Why this package?

This package exposes re-usable runtime type checking functions. This is useful for shrinking bundle sizes.

## How to install

Install `@analytics/type-utils` from [npm](https://www.npmjs.com/package/@analytics/type-utils).

```bash
npm install @analytics/type-utils
```

## API

Below is the api for `@analytics/type-utils`.

## `isBrowser`

Check if currently in browser context

```js
import { isBrowser } from '@analytics/type-utils'

if (isBrowser) {
  console.log('do things in browser env')
}
```

## `isNode`

Check if currently in Node.js context

```js
import { isNode } from '@analytics/type-utils'

if (isNode) {
  console.log('do things in node env')
}
```

## `isDeno`

Check if currently in Deno context

```js
import { isDeno } from '@analytics/type-utils'

if (isDeno) {
  console.log('do things in deno env')
}
```

## `isWebWorker`

Check if currently in WebWorker context

```js
import { isWebWorker } from '@analytics/type-utils'

if (isWebWorker) {
  console.log('do things in webworker env')
}
```

## `isJsDom`

Check if currently in JSDOM context

```js
import { isJsDom } from '@analytics/type-utils'

if (isJsDom) {
  console.log('do things in JSDOM env')
}
```

## `isString`

Check if value is `string`

```js
import { isString } from '@analytics/type-utils'

const xyz = 'hi'
console.log(isString(xyz))
// true
```

## `isNumber`

Check if value is `number`

```js
import { isNumber } from '@analytics/type-utils'

const xyz = 123
console.log(isNumber(xyz))
// true
```

## `isBoolean`

Check if value is `boolean`

```js
import { isBoolean } from '@analytics/type-utils'

const myBool = true
console.log(isBoolean(myBool))
// true
```

## `isPrimitive`

Check if value is primitive JS value.

```js
import { isPrimitive } from '@analytics/type-utils'

isPrimitive(true) // =>  true
isPrimitive({}) // => false
isPrimitive(0) // =>  true
isPrimitive('1') // =>  true
isPrimitive(1.1) // =>  true
isPrimitive(NaN) // =>  true
isPrimitive(Infinity) // =>  true
isPrimitive(function() {}) // => false
isPrimitive(Date), // => false
isPrimitive(null) // =>  true
isPrimitive(undefined) // =>  true
```

## `isArray`

Check if value is `array`

```js
import { isArray } from '@analytics/type-utils'

const myArr = ['x', 'y']
console.log(isArray(myArr))
// true
```

## `isObject`

Check if value is `object`

```js
import { isObject } from '@analytics/type-utils'

const myObj = { cool: 'hello' }
console.log(isObject(myObj))
// true
```

## `isUndefined`

Check if value is `undefined`

```js
import { isUndefined } from '@analytics/type-utils'

let myval
console.log(isUndefined(myval))
// true
```

## `isFunction`

Check if value is `function`

```js
import { isFunction } from '@analytics/type-utils'

function xyz() {}
console.log(isFunction(xyz))
// true
```

## `isClass`

Check if value is javascript `class`

```js
import { isClass } from '@analytics/type-utils'

class MyClass {}
console.log(isClass(MyClass))
// true
```

## `isPromise`

Check if value is javascript `promise`

```js
import { isPromise } from '@analytics/type-utils'

const myPromise = Promise.resolve()
console.log(isPromise(myPromise))
// true
```

## `isErrorLike`

Check if value is javascript `isErrorLike`

```ts
import { isErrorLike } from '@analytics/type-utils'

isErrorLike(new Error()) // True
isErrorLike({ name: "Error!", message: "This is an error", other: 0 }) // True
isErrorLike({}) // False
isErrorLike({ name: "Error", message: null }) // False
// Works as a typguard
const something = {name: "Error", message: "This is an error"} as unknown
if (isErrorLike(something)) {
  console.log(something.name) // No Typescript error
}
```

## `isRegex`

Check if value is regular expression.

```js
import { isRegex } from '@analytics/type-utils'

let myval = /pattern/gm
console.log(isRegex(myval))
// true
```

## `isNoOp`

Check if value is a `noOp` function.

```js
import { isNoOp } from '@analytics/type-utils'

function empty () { }
console.log(isNoOp(isNoOp))
// true
```

## `isTruthy`

Check if value is truthy.

```js
import { isTruthy } from '@analytics/types-utils'

console.log(isTruthy('')) // false
console.log(isTruthy('false')) // false
console.log(isTruthy('FALSE')) // false
console.log(isTruthy(0)) // false
console.log(isTruthy(null)) // false
console.log(isTruthy(undefined)) // false
console.log(isTruthy('true')) // true
console.log(isTruthy(1)) // true
console.log(isTruthy({})) // true
console.log(isTruthy([])) // true
console.log(isTruthy(function() { })) // true
```

## `isEmail`

Check if value is an email.

```js
import { isEmail } from '@analytics/type-utils'

console.log(isEmail('email@email.com'))
// true
console.log(isEmail('other-thing'))
// false
```

## `isElement`

Check if value is a a DOM node.

```js
import { isElement } from '@analytics/type-utils'

const formElement = document.querySelector('.my-form')
console.log(isElement(formElement))
// true
```


## `isNodeList`

Check if value is a list of DOM nodes.

```js
import { isNodeList } from '@analytics/type-utils'

const buttons = document.querySelectorAll('button')
console.log(isNodeList(buttons))
// true
```

## `isForm`

Check if value is a `noOp` function.

```js
import { isForm } from '@analytics/type-utils'

const formElement = document.querySelector('.my-form')
console.log(isForm(formElement))
// true
```

## Alternative libs

- [Native node types utils](https://nodejs.org/dist/latest-v17.x/docs/api/util.html#utiltypes)
- https://github.com/jonschlinkert/kind-of
- https://github.com/enricomarino/is
- https://github.com/mesqueeb/is-what
- https://github.com/stdlib-js/assert