export function isDefined ( a ) { return ! ! a || a === 0 || a === false ; } export function isFunction ( a ) { return typeof a === 'function' ; } export function isNumber ( a ) { return typeof a === 'number' ; } export function isObject ( a ) { return typeof a === 'object' && ! ! a ; } export function isString ( a ) { return typeof a === 'string' ; } export function isArrayLike ( a ) { return a && isFinite ( a . length ) && ! isString ( a ) && ! isFunction ( a ) ; } export function isDOM ( target ) { return target . nodeType || target instanceof SVGElement ; } export function isOwner ( obj , name ) { return obj . hasOwnProperty ( name ) ; }