import { isUndefined } from "@varunsridharan/js-is"
var var1 = 'your-value';

if( isUndefined(var1) ){
    alert('Var1 is defined')
}

if( isUndefined(var2) ){
    alert('Var1 is defined')
} else {
    alert('Var2 is NOT defined')
}

import { isNull } from "@varunsridharan/js-is"

isNull( null ); // true

isNull( 42 ); // false

import { isObject } from "@varunsridharan/js-is"

isObject( { foo: 'bar' } ); // true

isObject( null ); // false

isObject( 'foo' ); // false

import { isArguments } from "@varunsridharan/js-is"

var getArguments = function() {
	return arguments;
};

isArguments( getArguments() ); // true

isArguments( { foo: 'bar' } ); // false

import { isArray } from "@varunsridharan/js-is"

isArray( ['foo', 'bar', 'baz'] ); // true

isArray( {foo: 'bar'} ); // false

import { isBoolean } from "@varunsridharan/js-is"

isBoolean( true ); // true

isBoolean( false ); // true

isBoolean( 'value' ); // false

import { isTrue } from "@varunsridharan/js-is"

isTrue( true ); // true

isTrue( false ); // false

import { isFalse } from "@varunsridharan/js-is"

isFalse( false ); // true

isFalse( true ); // false

import { isDate } from "@varunsridharan/js-is"

isDate( new Date() ); // true

isDate( '20/09/2020' ); // false

import { isError } from "@varunsridharan/js-is"

isError( new Error() ); // true

isError( 'unknown error' ); // false

import { isFunction } from "@varunsridharan/js-is"

const tolowercase = ( string ) => String.toLowerCase.call( string );

function myfunction() {
	return 'Nothing';
}

isFunction( toString ); // true

isFunction( tolowercase ); // true

isFunction( myfunction ); // true

isFunction( { foo: bar } ); // false

import { isNan } from "@varunsridharan/js-is"

isNan( NaN ); // true

isNan( 1 ); // false

isNan( '1' ); // false

import { isNan } from "@varunsridharan/js-is"

isNull( null ); // true

isNull( 1 ); // false

isNull( '1' ); // false

import { isNumber } from "@varunsridharan/js-is"

isNumber( 42 ); // true

isNumber( '42' ); // false

isNumber( NaN ); // false

import { isNumeric } from "@varunsridharan/js-is"

isNumeric( 42 ); // true

isNumeric( '42' ); // true

isNumeric( NaN ); // false

import { isNumeric } from "@varunsridharan/js-is"

isNumeric( '42' ); // true

isNumeric( 'your-string' ); // true

isNumeric( 42 ); // false

isNumeric( NaN ); // false

import { isUndefined } from "@varunsridharan/js-is"

const var2 = 'somevalue';

isUndefined( var1 ); // true

isUndefined( var2 ); // false

isUndefined( 'your-string' ); // false

import { isPlainObject } from "@varunsridharan/js-is"

isPlainObject( {} ); // true

isUndefined( var2 ); // false

isUndefined( 'your-string' ); // false

import { isWindow } from "@varunsridharan/js-is"

isWindow( window ); // true

isWindow( document ); // false

import { isDocument } from "@varunsridharan/js-is"

isDocument( yourelem ); // true

isDocument( 'window' ); // false

import { isDocument } from "@varunsridharan/js-is"

isDocument( document ); // true

isDocument( window ); // false