extractNationalSignificantNumber(nationalDigits, setState) {
		if (!this.hasSelectedNumberingPlan) {
			return
		}
		const {
			nationalPrefix,
			nationalNumber,
			carrierCode
		} = extractNationalNumberFromPossiblyIncompleteNumber(
			nationalDigits,
			this.metadata
		)
		if (nationalNumber === nationalDigits) {
			return
		}
		this.onExtractedNationalNumber(
			nationalPrefix,
			carrierCode,
			nationalNumber,
			nationalDigits,
			setState
		)
		return true
	}
Extracts a national (significant) number from user input.
Google's library is different in that it only applies `national_prefix_for_parsing`
and doesn't apply `national_prefix_transform_rule` after that.
https://github.com/google/libphonenumber/blob/a3d70b0487875475e6ad659af404943211d26456/java/libphonenumber/src/com/google/i18n/phonenumbers/AsYouTypeFormatter.java#L539
@return {boolean} [extracted]