function filter( list ) {
	var out;
	var i;

	out = [];
	for ( i = 0; i < list.length; i++ ) {
		if ( RE_JSON.test( list[ i ] ) ) {
			out.push( list[ i ] );
		}
	}
	return out;
}
Filters a list of files for those having a `*.json` file extension.

@private
@param {Array<string>} list - file list
@returns {Array<string>} filtered list