Javascript Print format

// print format
//-- print("Hello, {0}! The answer is {1}.", "World", 42);
function format(fmt, ...args) {
    if (!fmt.match(/^(?:(?:(?:[^{}]|(?:\{\{)|(?:\}\}))+)|(?:\{[0-9]+\}))+$/)) {
        throw new Error('invalid format string.');
    }
    return fmt.replace(/((?:[^{}]|(?:\{\{)|(?:\}\}))+)|(?:\{([0-9]+)\})/g, (m, str, index) => {
        if (str) {
            return str.replace(/(?:{{)|(?:}})/g, m => m[0]);
        } else {
            if (index >= args.length) {
                throw new Error('argument index is out of range in format');
            }
            return args[index];
        }
    });
}