What's the simplest approach to check existence of deeply-nested object property in JavaScript? [duplicate]

Answer 1

Consider this utility function:

function defined(ref, strNames) {
    var name;
    var arrNames = strNames.split('.');

    while (name = arrNames.shift()) {        
        if (!ref.hasOwnProperty(name)) return false;
        ref = ref[name];
    } 

    return true;
}

Usage:

if (defined(YAHOO, 'Foo.Bar.xyz')) {
    // operate on YAHOO.Foo.Bar.xyz
}

Live demo: http://jsfiddle.net/DWefK/5/