setNegativeFormat(negativeFormat) {
    const settings = this.numberFormatFormatter().parse(negativeFormat);
    this.setNegativePrefix(settings.prefix);
    this.setNegativeSuffix(settings.suffix);
    this.setGroupingSize(settings.groupingSize);
    this.setMaximumFractionDigits(settings.maximumFractionDigits);
    this.setMinimumFractionDigits(settings.minimumFractionDigits);
    this.setMinimumIntegerDigits(settings.minimumIntegerDigits);
    this.setUsesGroupingSeparator(settings.usesGroupingSeparator);
  }
Configures this number formatter according to the given format string.
For most usages you should simply use
{@link NumberFormatter#setPositiveFormat} and configure the negative
prefix and suffix separately.

@param negativeFormat