Convert Javascript string in dot notation into an object reference

string-dot-notation-to-object

// pulled from SO http://stackoverflow.com/questions/6393943/convert-javascript-string-in-dot-notation-into-an-object-reference
// NOTE: Array.reduce() may not be available in older browsers

function index(obj,i) {return obj[i]}
'a.b.etc'.split('.').reduce(index, obj);

var obj = {a:{b:{etc:5}}};

index(obj,'a.b.etc');

index(obj,['a','b','etc']);	// works with both strings and lists

index(obj,'a.b.etc', 123);	// setter-mode - third argument (possibly poor form)

index(obj,'a.b.etc');