export function isObject ( obj ) { return typeof obj === 'object' && ! Array . isArray ( obj ) && obj !== null ; } export function isArray ( array ) { return Array . isArray ( array ) ; } export function isBoolean ( bool ) { return typeof bool === 'boolean' ; } export function isString ( string ) { return typeof string === 'string' ; } export function isNumber ( number ) { return typeof number === 'number' ; } export function isNull ( _null ) { return _null === null ; }