How to use the belter/src.objFilter function in belter

function track(payload = {}) : LoggerType {
        if (!isBrowser()) {
            return logger; // eslint-disable-line no-use-before-define
        }

        const trackingPayload : Payload = objFilter(payload);

        for (const builder of trackingBuilders) {
            extendIfDefined(trackingPayload, builder(trackingPayload));
        }

        print(LOG_LEVEL.DEBUG, 'track', trackingPayload);
        tracking.push(trackingPayload);

        return logger; // eslint-disable-line no-use-before-define
    }

function log(level, event, payload) {
    if (payload === void 0) {
      payload = {};
    }

    if (!isBrowser()) {
      return logger; // eslint-disable-line no-use-before-define
    }

    if (prefix) {
      event = prefix + "_" + event;
    }

    var logPayload = _extends({}, objFilter(payload), {
      timestamp: Date.now().toString()
    });

    for (var _i6 = 0; _i6 < payloadBuilders.length; _i6++) {
      var builder = payloadBuilders[_i6];
      extendIfDefined(logPayload, builder(logPayload));
    }

    enqueue(level, event, logPayload);
    print(level, event, logPayload);
    return logger; // eslint-disable-line no-use-before-define
  }

function track(payload) {
    if (payload === void 0) {
      payload = {};
    }

    if (!isBrowser()) {
      return logger; // eslint-disable-line no-use-before-define
    }

    var trackingPayload = objFilter(payload);

    for (var _i8 = 0; _i8 < trackingBuilders.length; _i8++) {
      var builder = trackingBuilders[_i8];
      extendIfDefined(trackingPayload, builder(trackingPayload));
    }

    print(LOG_LEVEL.DEBUG, 'track', trackingPayload);
    tracking.push(trackingPayload);
    return logger; // eslint-disable-line no-use-before-define
  }

function log(level : $Values, event : string, payload = {}) : LoggerType {

        if (!isBrowser()) {
            return logger; // eslint-disable-line no-use-before-define
        }

        if (prefix) {
            event = `${ prefix }_${ event }`;
        }

        const logPayload : Payload = {
            ...objFilter(payload),
            timestamp: Date.now().toString()
        };

        for (const builder of payloadBuilders) {
            extendIfDefined(logPayload, builder(logPayload));
        }

        enqueue(level, event, logPayload);
        print(level, event, logPayload);

        return logger; // eslint-disable-line no-use-before-define
    }