How to use the @microsoft/recognizers-text-number.Constants.SYS_NUM_INTEGER function in @microsoft/recognizers-text-number

let year = -1;
        let er: ExtractResult;
        if (isChinese) {
            let yearNum = 0;
            er = this.integerExtractor.extract(yearStr).pop();
            if (er && er.type === NumberConstants.SYS_NUM_INTEGER) {
                yearNum = Number.parseInt(this.numberParser.parse(er).value);
            }

            if (yearNum < 10) {
                yearNum = 0;
                for (let index = 0; index < yearStr.length; index++) {
                    let char = yearStr.charAt(index);
                    yearNum *= 10;
                    er = this.integerExtractor.extract(char).pop();
                    if (er && er.type === NumberConstants.SYS_NUM_INTEGER) {
                        yearNum += Number.parseInt(this.numberParser.parse(er).value);
                    }
                }
                year = yearNum;
            }
            else {
                year = yearNum;
            }
        }
        else {
            year = Number.parseInt(yearStr, 10);
        }

        return year === 0 ? -1 : year;
    }

private convertChineseToNumber(source: string): number {
        let num = -1;
        let er = this.integerExtractor.extract(source).pop();
        if (er && er.type === NumberConstants.SYS_NUM_INTEGER) {
            num = Number.parseInt(this.numberParser.parse(er).value);
        }
        return num;
    }

private convertYear(yearStr: string, isChinese: boolean): number {
        let year = -1;
        let er: ExtractResult;
        if (isChinese) {
            let yearNum = 0;
            er = this.integerExtractor.extract(yearStr).pop();
            if (er && er.type === NumberConstants.SYS_NUM_INTEGER) {
                yearNum = Number.parseInt(this.numberParser.parse(er).value);
            }

            if (yearNum < 10) {
                yearNum = 0;
                for (let index = 0; index < yearStr.length; index++) {
                    let char = yearStr.charAt[index];
                    yearNum *= 10;
                    er = this.integerExtractor.extract(char).pop();
                    if (er && er.type === NumberConstants.SYS_NUM_INTEGER) {
                        yearNum += Number.parseInt(this.numberParser.parse(er).value);
                    }
                }
            }
            else {
                year = yearNum;

private parseChineseWrittenNumberToValue(source: string): number {
        let num = -1;
        let er = this.integerExtractor.extract(source);
        if (er && er[0].type === NumberConstants.SYS_NUM_INTEGER) {
            num = Number.parseInt(this.config.numberParser.parse(er[0]).value);
        }

        return num;
    }
}

private convertChineseYearToNumber(source: string): number {
        let year = 0;
        let er = this.config.integerExtractor.extract(source).pop();
        if (er && er.type === NumberConstants.SYS_NUM_INTEGER) {
            year = Number.parseInt(this.config.numberParser.parse(er).value);
        }
        if (year < 10) {
            year = 0;
            for (let i = 0; i < source.length; i++) {
                let char = source.charAt(i);
                year *= 10;
                let er = this.config.integerExtractor.extract(char).pop();
                if (er && er.type === NumberConstants.SYS_NUM_INTEGER) {
                    year += Number.parseInt(this.config.numberParser.parse(er).value);
                }
            }
        }
        return year < 10 ? -1 : year;
    }

private convertChineseYearToNumber(source: string): number {
        let year = 0;
        let er = this.config.integerExtractor.extract(source).pop();
        if (er && er.type === NumberConstants.SYS_NUM_INTEGER) {
            year = Number.parseInt(this.config.numberParser.parse(er).value);
        }
        if (year < 10) {
            year = 0;
            for (let i = 0; i < source.length; i++) {
                let char = source.charAt(i);
                year *= 10;
                let er = this.config.integerExtractor.extract(char).pop();
                if (er && er.type === NumberConstants.SYS_NUM_INTEGER) {
                    year += Number.parseInt(this.config.numberParser.parse(er).value);
                }
            }
        }
        return year < 10 ? -1 : year;
    }

let year = -1;
        let er: ExtractResult;
        if (isChinese) {
            let yearNum = 0;
            er = this.integerExtractor.extract(yearStr).pop();
            if (er && er.type === NumberConstants.SYS_NUM_INTEGER) {
                yearNum = Number.parseInt(this.numberParser.parse(er).value);
            }

            if (yearNum < 10) {
                yearNum = 0;
                for (let index = 0; index < yearStr.length; index++) {
                    let char = yearStr.charAt[index];
                    yearNum *= 10;
                    er = this.integerExtractor.extract(char).pop();
                    if (er && er.type === NumberConstants.SYS_NUM_INTEGER) {
                        yearNum += Number.parseInt(this.numberParser.parse(er).value);
                    }
                }
            }
            else {
                year = yearNum;
            }
        }
        else {
            year = Number.parseInt(yearStr, 10);
        }

        return year === 0 ? -1 : year;
    }