Type

Tiny library for determining the type.

Correctly handles arrays and null and can detection different objects for the name of the constructor.

Everything works out of the box.

Size: 133 B.

Install

npm i ariarzer/type

Usage

const type = require('type');

type([]); //=> 'array'
type(new Date()); //=> 'object'

Also you can use the second argument true to detection objects. In this case the constructor name is returned in lowercase.

type(new Date(), true); //=> 'date'
type(new myObject(), true); //=> 'myobject'

Configuration

Modes:

• Normal: works like almost typeof, but it is correct to handle null and arrays.

• All: distinguishes types of objects, returns the name of the object constructor in lowercase.

Examples:

	normal	all
undefined	'undefined'	'undefined'
null	'null'	'null'
[]	'array'	'array'
Symbol()	'symbol'	'symbol'
new WeakSet()	'object'	'weakset'
new Date()	'object'	'date'
new MyObject()	'object'	'myobject'
document.createElement('div')	'object'	'htmldivelement'

const config = {
  mode: 'all', // string: 'all' || 'normal' (default: 'normal')
}

Example of using modes:

const type = require('type');

const myType = type.create({mode: 'all'});
myType(new myObject()); //=> 'myobject'

// But, you can run that... 
type(new myObject(), true); //=> 'myobject';
// ...and get a similar result. 

Custom types:

If you want to detect s custom type, for example, the days of the week, you can do this with use a config.

// write a config..
const week =  ['sunday', 'monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday'];

const customTypes = week.map((item, index) => {
  return {
    name: item,
    is: function (arg) {
      return type(arg, true) === 'date' && arg.getDay() === index;
    },
  };
});

// ...create a custom function...
const daysDetector = type.create(customTypes);

// ..and use it
daysDetector(new Date(2019, 4, 25)) //=> 'saturday'  (May 25 2019) 
daysDetector(new Date(2019, 4, 26)) //=> 'sunday'    (May 26 2019) 
daysDetector(new myObject()) //=> 'object'

You can use modes and custom types together.