@fav/type.is-empty

Checks whether a value is empty or not.

"fav" is an abbreviation of "favorite" and also the acronym of "for all versions". This package is intended to support all Node.js versions and many browsers as possible. At least, this package supports Node.js >= v0.10 and major Web browsers: Chrome, Firefox, IE11, Edge, Vivaldi and Safari.

Install

To install from npm:

$ npm install --save @fav/type.is-empty

NOTE: npm < 2.7.0 does not support scoped package, but old version Node.js supports it. So when you use such older npm, you should download this package from github.com, and move it in node_modules/@fav/type.is-empty/ directory manually.

Usage

For Node.js:

var isEmpty = require('@fav/type.is-empty');

isEmpty([]); // => true
isEmpty(['a']); // => false
isEmpty.not([]); // => false
isEmpty.not(['a']); // => true

isEmpty({}); // => true
isEmpty({ a: 1 }); // => false
isEmpty.not({}); // => false
isEmpty.not({ a: 1 }); // => true

For Web browsers:

<script src="fav.type.is-empty.min.js"></script>
<script>
var isEmpty = fav.type.isEmpty;
isEmpty([]); // => true
isEmpty.not([]); // => false
</script>

API

isEmpty(value) : boolean

Checks if value is empty.

Definition of "empty" is different by data type.

• undefined: always empty.
• null: always empty.
• array: empty if it has no element.
• plain object: empty if it has no property.
• NodeList: empty if it has no element.
• HTMLCollection: empty if it has no element.
• others: always not empty.

This function always returns false for other collections like Map, Set, typed-array and so on, because I think there are few needs to check them without knowing their data types. If data type of a collection is known, its own API to get size of itself should be used.

Parameter:

| Parameter | Type | Description | |-----------|:------:|-------------------------| | value | any | The value to be checked |

Return:

True, if value is empty.

Type: boolean

isEmpty.not(value) : boolean

Checks if value is not empty.

This function always returns a negative boolean of isEmpty(value).

Parameter:

| Parameter | Type | Description | |-----------|:------:|-------------------------| | value | any | The value to be checked |

Return:

True, if value is not empty.

Type: boolean

Checked

Node.js (4〜)

| Platform | 4 | 5 | 6 | 7 | 8 | 9 | 10 | |:---------:|:------:|:------:|:------:|:------:|:------:|:------:|:------:| | macOS |◯|◯|◯|◯|◯|◯|◯| | Windows10 |◯|◯|◯|◯|◯|◯|◯| | Linux |◯|◯|◯|◯|◯|◯|◯|

io.js (1〜3)

| Platform | 1 | 2 | 3 | |:---------:|:------:|:------:|:------:| | macOS |◯|◯|◯| | Windows10 |◯|◯|◯| | Linux |◯|◯|◯|

Node.js (〜0.12)

| Platform | 0.8 | 0.9 | 0.10 | 0.11 | 0.12 | |:---------:|:------:|:------:|:------:|:------:|:------:| | macOS |◯|◯|◯|◯|◯| | Windows10 |◯|◯|◯|◯|◯| | Linux |◯|◯|◯|◯|◯|

Web browsers

| Platform | Chrome | Firefox | Vivaldi | Safari | Edge | IE11 | |:---------:|:------:|:-------:|:-------:|:------:|:------:|:------:| | macOS |◯|◯ |◯ |◯| -- | -- | | Windows10 |◯|◯ |◯ | -- |◯|◯| | Linux |◯|◯ |◯ | -- | -- | -- |

License

Copyright (C) 2017 Takayuki Sato

This program is free software under MIT License. See the file LICENSE in this distribution for more details.