Question

im struggling with a script where a method/object returns undefined

var Lang = new function(){
    this.get = function(str, trans){
        if(TRANSLATE[str]){
            var str = TRANSLATE[str][LANG];
            if(count_obj(trans) > 0){
                for(var key in trans){
                    str = str.replace('%'+key+'%', trans[key]);
                }
            }

            return str;
        }
    };
};

function Language(){
    this.tbl_list = null;

    this.append = function(string, obj, index){
        var row = $('<tr></tr>')
            .append('<td class="list_row">'+js2txt(string)+'</td>');

        for(var key in obj){
            row.append('<td class="list_row">'+js2txt(obj[key])+'</td>');
        }
        var td = $('<td class="list_row"></td>').appendTo(row);
        //var inp_edit = $('<input type="button" value="'+Lang.get('BTN_EDIT')+'" />');
        alert(Lang.get);
        List.append_row(row, this.tbl_list, index);
    };
};
alert(Lang.get);

inside the Language object Lang.get returns undefined, but outside it returns the function!?

Answer 1

> var Lang = new function(){
>     this.get = function(str, trans){
>         if(TRANSLATE[str]){
>             var str = TRANSLATE[str][LANG];
>             if(count_obj(trans) > 0){
>                 for(var key in trans){
>                     str = str.replace('%'+key+'%', trans[key]);
>                 }
>             }
>             return str;
>         }
>     }; };

I don’t see a reason for using new above, it’s just a waste of resources. Since Lang doesn’t seem to be called as a constructor, it should, by convention, start with a lower case letter. Why not:

var lang = {
    get: function(str, trans) {
        // function body
    }
};

.

> function Language(){
>     this.tbl_list = null;
> 
>     this.append = function(string, obj, index){
>     /* snip */
>         alert(Lang.get);
>     /* snip */
>     }; };


alert(Lang.get);  // shows source of Lang.get

inside the Language object Lang.get returns undefined, but outside it returns the function!?

How are you calling it? It appears to be a constructor, so:

var x = new Language();  // Create instance lf Language
x.append();  // Shows Lang.get

Which is the same result as calling Language as a function. What is the issue?

Also, the jQuery stuff seems to be very inefficient. You might want to work on that. e.g.

> var row = $('<tr></tr>')
>             .append('<td class="list_row">'+js2txt(string)+'</td>');

would be much better as:

var row = $('<tr><td class="list_row">'+js2txt(string)+'</td></tr>');

Or even better would be to create a single row with the structure you want, clone it for each row, then just replace the content of the cell.