desc export const isEmptyArray = ( arr ) => { return Array . isArray ( arr ) && arr . length === 0 ; } ; desc export const isEmptyObject = ( obj ) => { return ( Object . prototype . toString . call ( obj ) === '[object Object]' && JSON . stringify ( obj ) === '{}' ) ; } ; desc export const isObject = ( obj ) => { return Object . prototype . toString . call ( obj ) === '[object Object]' ; } ; desc export const isString = ( str ) => { return Object . prototype . toString . call ( str ) === '[object String]' ; } ; desc export const isNumber = ( obj ) => { return Object . prototype . toString . call ( obj ) === '[object Number]' ; } ;