jquery - Javascript string start equality -

i have array of objects, each object has property filename (string):

i group these objects (on filename property) same naming starting beginning last occurrence of $ sign.

so achieve grupation (each group should new array):

blue$ blue$_35      blue_paint$ blue_paint$_35   blue_paint$_55  01_red_carper_floor$ 01_red_carper_floor$_and_roof  01_red$   green_car$ 

some objects have multiple while remain single.

i using javascript , jquery.

i found similar question not quite same:

find longest common starting substring in set of strings

jsfiddle

var objects = [     {filename:"green$1"},     {filename:"green$2"},     {filename:"green$3"},     {filename:"green$4"},     {filename:"blue$1$1"},     {filename:"blue$1"},     {filename:"red$1"},     {filename:"green$5"}, ]  var groups = [];  (var = 0; < objects.length; i++){     var filename = objects[i].filename     var n = filename.lastindexof("$");     var groupname = filename.substring(0, n);     if (groups[groupname] != undefined)         groups[groupname].push(objects[i]);     else {         groups[groupname] = [];         groups[groupname].push(objects[i]);     } }  console.log(groups);