Since you want the text between the first { and last }:
derp.toString().replace(/^[^{]*{\s*/,'').replace(/\s*}[^}]*$/,'');
Note that I broke the replacement down into to regexes instead of one regex covering the whole thing (.replace(/^[^{]*{\s*([\d\D]*)\s*}[^}]*$/,'$1')) because it's much less memory-intensive.
