@lvchengbin/is

Is

A JavaScript library for checking the type of a value for browsers.

Installing

npm i @lvchengbin/is --save

Usage

Generally, when we are using some toolkit such as rollup, we don't want to compile a huge library into our project, therefore, to import the files you really need.

import isFunction from '@lvchengbin/is/src/function';
import array from '@lvchengbin/is/src/array';

isFunction( async () => {} );
isArray( [] );

If you want to invoke the whole package:

import is from '@lvchengbin/is';

is.function( () => {} );
is.array( [] );

Using in browsers

If you want to invoke this package to browsers with <script> tag or something like that, use is.js. For old browsers which are not supporting ES5 syntax, use is.bc.js.

Method List

is.arguments

import isArguments from '@lvchengbin/is/src/arguments';

is.array

import isArray from '@lvchengbin/is/src/array';

is.arrowFunction

For checking if a function is an arrow function.

import isArrowFunction from '@lvchengbin/is/src/arrow-function';

isArrowFunction( () => {} ); // returns true

is.asyncFunction

For checking if a function is an async function.

import isAsyncFunction from '@lvchengbin/is/src/async-function';

isAsyncFunction( async () => {} ); // returns true

is.boolean

import isBoolean from '@lvchengbin/is/src/boolean';

is.date

For checking if an object is a Date instance.

import isDate from '@lvchengbin/is/src/date';

isDate( new Date ); // return true

is.email

For checking if the value is an email address.

import isEmail from '@lvchengbin/is/src/email';

isEmail( '[e-mail]' ); // returns true

is.empty

For checking if a value is empty, and empty values include empty object ({}), empty string (''), empty array ([]), number 0, false.

import isEmpty from '@lvchengbin/is/src/empty';

isEmpty( '' ); // return true
isEmpty( [] ); // return true
isEmpty( {} ); // return true
isEmpty( 0 ); // return true
isEmpty( false ); // return true

is.error

For checking if an object is an Error instance.

import isError from '@lvchengbin/is/src/error';

isError( new Error ); // returns true

is.false

For checking if a value is false, if the second argument is true (by default), the function will check a generalized false, it means that the following strings all mean false: "false", "no", "0", "", "nay", "n", "disagree".

import isFalse from '@lvchengbin/is/src/false';

isFalse( false ); // returns true
isFalse( 'false' ); // returns true
isFalse( 'false', false ); // returns false

is.function

import isFunction from '@lvchengbin/is/src/function';

is.integer

import isInteger from '@lvchengbin/is/src/integer';

is.iterable

import isIterable from '@lvchengbin/is/src/iterable';

is.number

import isNumber from '@lvchengbin/is/src/number';

is.object

import isObject from '@lvchengbin/is/src/object';

is.promise

import isPromise from '@lvchengbin/is/src/promise';

is.regexp

import isRegExp from '@lvchengbin/is/src/regexp';

is.string

import isString from '@lvchengbin/is/src/string';

is.true

For checking if a value is true, if the second argument is true (by default), the function will check a generalized true, it means that the following strings all mean true: "true", "true", "yes", "ok", "1", "yea", "yep", "y", "agree".

import isTrue from '@lvchengbin/is/src/true';
isTrue( true ); // returns true
isTrue( 'true' ); // returns true
isTrue( 'true', false ); // returns false

is.undefined

import isUndefined from '@lvchengbin/is/src/undefined';

is.url

import isUrl from '@lvchengbin/is/src/url';

is.node

impor isNode from '@lvchengbin/is/src/node';