is-of-type

A collection of utility functions to help deal with JavaScript’s built-in types and add readability to your code. Only ~430 bytes when minified and gzipped.

Install

`` bash
npm install is-of-type --save

or

yarn add is-of-type
`

Usage

All of the functions exports by this package have the following signature: fn(arg: Any): boolean.

This package helps you turn:

`javascript
if (x !== null && x !== undefined) {
//...
}
if (typeof fn === 'function') {
fn();
}
if (typeof n === 'number' && !isNaN(n)) {
// ...
}
if (typeof s === 'string' && s.length > 0) {
// ...
}
if (typeof o === 'object') {
// ...
}
`

into

`javascript
import {
isDefinedAndNotNull,
isFunction,
isNumberAndNotNaN,
isNonEmptyString,
isObject,
} from 'is-of-type';

if (isDefinedAndNotNull(x)) {
//...
}
if (isFunction(fn)) {
fn();
}
if (isNumberAndNotNaN(n)) {
// ...
}
if (isNonEmptyString(s)) {
// ...
}
if (isObject(o)) {
/*
* Identical to typeof o === 'object', so let’s null, Array, Set, Map etc. pass
* You can compose your own method to improve this, e.g:
* const isRealObject = (o) => {
* return isObjecy(o) && !isNull(o);
* }
*/
}
`

And many other checks that are easier to read and composable.

List of Functions

This package exports the following utilities:
- isDefined (or isDef)
- isNull
- isDefinedAndNotNull
- isDefAndNotNull
- isArray
- isNonEmptyArray
- isBoolean (or isBool)
- isFunction (or isFn)
- isObject
- Strict check typeof o === object'
- So returns true for Array, null, Set, Map, Date, and regex.
- isDate
- isString
- isNonEmptyString
- isNumber
- isNaN
- isNumberAndNotNaN`