def js_prerelease(command, strict=False):
    """decorator for building minified js/css prior to another command"""
    class DecoratedCommand(command):
        def run(self):
            jsdeps = self.distribution.get_command_obj('jsdeps')
            if not is_repo and all(exists(t) for t in jsdeps.targets):
                # sdist, nothing to do
                command.run(self)
                return

            try:
                self.distribution.run_command('jsdeps')
            except Exception as e:
                missing = [t for t in jsdeps.targets if not exists(t)]
                if strict or missing:
                    log.warn('rebuilding js and css failed')
                    if missing:
                        log.error('missing files: %s' % missing)
                    raise e
                else:
                    log.warn('rebuilding js and css failed (not a problem)')
                    log.warn(str(e))
            command.run(self)
            update_package_data(self.distribution)
    return DecoratedCommand