Method get_first_header

web/src/js/flow/utils.ts:21–39

(
        message: HTTPMessage,
        regex: RegExp,
    )

    }

    static get_first_header(
        message: HTTPMessage,
        regex: RegExp,
    ): string | undefined {
        let messageLookups = _headerLookups.get(message);
        if (!messageLookups) {
            messageLookups = new Map();
            _headerLookups.set(message, messageLookups);
        }
        let ret = messageLookups.get(regex);
        if (ret === undefined) {
            const header = message.headers.find(([name, _]) =>
                regex.test(name),
            );
            ret = header ? header[1] : false;
            messageLookups.set(regex, ret);
        }
        return ret !== false ? ret : undefined;
    }

    static match_header(message, regex) {
        const headers = message.headers;