javascript - What can I use instead of typeof in JS -

if have javascript array objects inside, this

articlesparams[itemid].properties.loaded 

if try this:

if ( typeof articlesparams[itemid].properties.loaded != 'undefined' && ...) {     // something... } 

i have encountered problem if articleparams[itemid].properties undefined got error: cannot read property 'properties' of undefined.

so in case should stupid this:

if ( typeof articlesparams[itemid].properties != 'undefined' &&           typeof articlesparams[itemid].properties.loaded != 'undefined'  && ...) {     // something... } 

is equivalent in javascript in php isset() ?

an alternative this, quite typical in js:

if (articlesparams[itemid] &&     articlesparams[itemid].properties &&       articlesparams[itemid].properties.loaded  && ...) {     // something... } 

or this:

var item = articlesparams[itemid]; if (item && item.properties && item.properties.loaded  && ...) {     // something... } 

one point note not work if want if statement execute if loaded false. in case, better off checking if undefined using typeof.