is.js

A collection of user-defined type guards to handle some of Javascript's less-than-ideal behavior.

Installing

``bash
$ npm install is-js
$ yarn add is-js
`

Usage

- array
- bigint
- bool
- date
- error
- func
- nil
- number
- object
- promise
- promiseLike
- regex
- string
- symbol
- undef

$3

▸ array(arg): arg is any[]

Determines if the argument is an array.

remarks
Defaults to the native Array.isArray method, if present.

#### Parameters

| Name | Type |
| :------ | :------ |
| arg | any |

#### Returns

arg is any[]

true if the given argument is an array

___

$3

▸ bigint(value): boolean

Determines if the argument is a BigInt

remarks
This method does not support polyfilled BigInt implementations; please defer
to the library in use to determine the type of an unknown argument.

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| value | unknown | Value in question |

#### Returns

boolean

true if the given argument is a native BigInt

___

$3

▸ bool(value): value is boolean

Determines if the argument is a boolean

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| value | unknown | Value in question |

#### Returns

value is boolean

true if the given argument is a boolean

___

$3

▸ date(value): value is Date

Determines if the argument is a date.

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| value | unknown | Value in question |

#### Returns

value is Date

true if the given argument is a date

___

$3

▸ error(value): value is Error

Determines if the argument is an error.

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| value | unknown | Value in question |

#### Returns

value is Error

true if the given argument is an error

___

$3

▸ func(value): value is Function

Determines if the argument is a function.

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| value | unknown | Value in question |

#### Returns

value is Function

true if the given argument is a function

___

$3

▸ nil(value): value is null

Determines if the argument is null

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| value | unknown | Value in question |

#### Returns

value is null

true if the given argument is null

___

$3

▸ number(value): value is number

Determines if the argument is a number

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| value | unknown | Value in question |

#### Returns

value is number

true if the given argument is a number

___

$3

▸ object(value): value is Object

Determines if the argument is an object.

remarks
Nearly everything in Javascript is an object; this method discerns between
native primitives (e.g. true, 3, some text) and their object-wrapped
variants (Boolean, Number, String)

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| value | unknown | Value in question |

#### Returns

value is Object

true if the given argument is an object

___

$3

▸ promise(value): value is Promise

Determines if the argument is a native promise.

remarks
Some libraries and frameworks still include their own polyfilled Promises,
in which case this method is unreliable. If you are using such a library,
please defer to the provided Promise implementation or use promiseLike

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| value | unknown | Value in question |

#### Returns

value is Promise

true if the given argument is a string

___

$3

▸ promiseLike(value): value is Object

Determines if the argument conforms to the minimal interface of a Promise;
that is, it has a method named then.

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| value | unknown | Value in question |

#### Returns

value is Object

true if the given argument conforms to the Promise interface

___

$3

▸ regex(value): value is RegExp

Determines if the argument is a regular expression.

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| value | unknown | Value in question |

#### Returns

value is RegExp

true if the given argument is a regular expression

___

$3

▸ string(value): value is string

Determines if the argument is a string.

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| value | unknown | Value in question |

#### Returns

value is string

true if the given argument is a string

___

$3

▸ symbol(value): value is Symbol

Determines if the argument is a symbol

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| value | unknown | Value in question |

#### Returns

value is Symbol

true if the given argument is a symbol

___

$3

▸ undef(value): value is undefined

Determines if the argument is undefined

#### Parameters

| Name | Type | Description |
| :------ | :------ | :------ |
| value | unknown | Value in question |

#### Returns

value is undefined

true if the given argument is undefined`