Changing forEach loop to for-loop in javascript

Question

I currently have a forEach loop like this.

var videoUrls ={};
ytplayer.config.args.url_encoded_fmt_stream_map.split(',')
.forEach(function(item) {
    var obj = { };
    item.split('&')
    .forEach(function(param) {
       param = param.split('=');
       obj[param[0]] = decodeURIComponent(param[1]);

});
videoUrls[obj.quality] = obj;});

Since IE is not supporting forEach loop, I tried to convert this to for loop.

var videoUrls ={};
var typea= ytplayer.config.args.url_encoded_fmt_stream_map.split(',');
for (var item=0; item<typea.length; item++){
   var obj= {};
   var typeb= typea[item].split('&');
   for (var param=0; param<typeb.length; param++){

       typeb[param]= typeb[param].split('=');
       obj[typeb[0]] = decodeURIComponent(typeb[1]);

}
videoUrls[obj.quality]= obj;
}

But when I run the script the results were different. What did i do wrong?

Thanks in advance.

Answer 1

it should be:

typeb[param]= typeb[param].split('=');
obj[typeb[param][0]] = decodeURIComponent(typeb[param][1]);

Because the other loop is:

param = param.split('=');
obj[param[0]] = decodeURIComponent(param[1]);

Not:

obj[item.split("&")[0]] = decodeURIComponent(item.split("&")[1])

If it's still not clear, here is a simpler explanation:

typeb === item.split("&");
typeb[param] === param;

Answer 2

The problem is here:

for (var param=0; param<typeb.length; param++) {
    typeb[param]= typeb[param].split('=');
    obj[typeb[0]] = decodeURIComponent(typeb[1]);
}

You're overwriting an element of the array you're iterating over ( typeb[param] ) and then using a hardcoded index into the same array ( typeb[1] )

Should be more like:

for (var param=0; param<typeb.length; param++) {
    var arr = typeb[param].split('=');
    obj[arr[0]] = decodeURIComponent(arr[1]);
}

Answer 3

And you cannot use library like jQuery? It is for this reason jQuery is built. If you cannot then i think this is what you need to do obj[typeb[param][0]] = decodeURIComponent(typeb[param][1]);