Javascript string replace not working [duplicate]

Answer 1

The problem is the returned value of the replace method is not assigned:

description = description.replace("<?player>", req.session.player);

JS Fiddle: http://jsfiddle.net/LEBRK/

Answer 2

replace method returns new string, so you need to assign it to your description variable:

var description = "<?player>, you are in a room.";

description = description.replace("<?player>", 'Bill'); // description now is "Bill, you are in a room."

Answer 3

You must assign your variable to the new altered string, because replace doesn't update your variable:

var description = "<?player>, you are in a room.";
description = description.replace('<?player>', req.session.player);

Moreover, if you want to replace all occurrences of '<\?player>' instead of only the first one, then use a regular expression with g (global) flag:

var description = "<?player>, you are in a room.";
description = description.replace(/<\?player>/g, req.session.player);

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For full information, read https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace. Some quotes:

Returns a new string with some or all matches of a pattern replaced by a replacement.

This method does not change the String object it is called on. It simply returns a new string.

To perform a global search and replace, either include the g switch in the regular expression