checking/assigning from object tree in node.js / javascript -

doing following risking exception 'there no bar on undefined'

var obj = o.foo.bar 

the way can think of doing above safely :

var obj = (o && o.foo && o.foo.bar ) ? o.foo.bar : null; 

or putting entire thing in try/catch not option in cases me.. , results in more code if want different thing happen depending on property missing.

is there concise way perform assignment safely?

** update **

tweaked @techfoobar's answer

function resolve(obj, propertypath) {     if (!propertypath) return;      var props = propertypath.split('.');     var o = obj;     for(var in props) {         o = o[props[i]];         if(!o) return false;     }     return o; }  var res = resolve(obj, 'apiresponse.commandresponse'); if (res){    (var in res){ 

seems it's going get...

one way moving function can re-use in multiple scenarios regardless of depth need go:

function resolve(_root) {    if(arguments.length == 1) return _root; // in case root passed    var o = _root;    for(var i=1; i<arguments.length; i++) {       o = o[arguments[i]];       if(!o) return undefined;    }    return o; } 

for example object var o = {x: {y:10, c:{h: 20}}};, can use like:

resolve(o, 'x') gives {y:10, c:{h: 20}}

resolve(o, 'x', 'c', 'h') gives 20

whereas

resolve(o, 'x', 'c', 'boo') gives undefined

in case, can use like:

var obj = resolve(o, 'foo', 'bar'); if(obj !== undefined) { // resolved    // stuff ... }