How to use the @microsoft/recognizers-text.RegExpUtility.getFirstMatchIndex function in @microsoft/recognizers-text

isConnectorToken(source: string): boolean {

        return (source === "" ||
            RegExpUtility.getFirstMatchIndex(this.prepositionRegex, source).matched ||
            RegExpUtility.getFirstMatchIndex(this.connectorRegex, source).matched);
    }
}

getBetweenTokenIndex(text: string): { matched: boolean; index: number; } {
        return RegExpUtility.getFirstMatchIndex(this.beforeRegex, text);
    }
}

getBetweenTokenIndex(source: string): { matched: boolean; index: number; } {
        return RegExpUtility.getFirstMatchIndex(this.betweenRegex, source);
    }

getSwiftDayOrMonth(source: string): number {
        let trimedText = source.trim().toLowerCase();
        let swift = 0;

        if (RegExpUtility.getFirstMatchIndex(this.nextPrefixRegex, trimedText).matched) {
            swift = 1;
        }

        if (RegExpUtility.getFirstMatchIndex(this.previousPrefixRegex, trimedText).matched) {
            swift = -1;
        }

        return swift;
    }

isConnectorToken(source: string): boolean {
        let trimmed = source.trim();
        return trimmed === ""
            || RegExpUtility.getFirstMatchIndex(this.prepositionRegex, source).matched
            || RegExpUtility.getFirstMatchIndex(this.connectorRegex, source).matched;
    }
}

getBetweenTokenIndex(source: string): { matched: boolean; index: number; } {
        return RegExpUtility.getFirstMatchIndex(this.beforeRegex, source);
    }

getSwiftYear(source: string): number {
        let trimedText = source.trim().toLowerCase();
        let swift = -10;
        if (RegExpUtility.getFirstMatchIndex(this.nextPrefixRegex, trimedText).matched) {
            swift = 1;
        }

        if (RegExpUtility.getFirstMatchIndex(this.previousPrefixRegex, trimedText).matched) {
            swift = -1;
        }
        else if (RegExpUtility.getFirstMatchIndex(this.thisPrefixRegex, trimedText).matched) {
            swift = 0;
        }

        return swift;
    }

getFromTokenIndex(text: string): { matched: boolean; index: number; } {
        return RegExpUtility.getFirstMatchIndex(this.fromRegex, text);
    }

getFromTokenIndex(source: string): { matched: boolean; index: number; } {
        return RegExpUtility.getFirstMatchIndex(this.fromRegex, source);
    }

isLastCardinal(source: string): boolean {
        let trimedText = source.trim().toLowerCase();
        return RegExpUtility.getFirstMatchIndex(this.previousPrefixRegex, trimedText).matched;
    }
}