How to use the igniteui-angular.IgxNumberSummaryOperand.average function in igniteui-angular

public operate(data?: any[]): IgxSummaryResult[] {
        const result = [];
        result.push(
            {
                key: "min",
                label: "min",
                summaryResult: IgxNumberSummaryOperand.min(data)
            }, {
                key: "max",
                label: "max",
                summaryResult: IgxNumberSummaryOperand.max(data)
            }, {
                key: "average",
                label: "average",
                summaryResult: data.length ? IgxNumberSummaryOperand.average(data).toFixed(2) : null
            });

        return result;
    }
}

public operate(data?: any[]): IgxSummaryResult[] {
        const result = [];
        const avg = IgxNumberSummaryOperand.average(data);
        result.push({
            key: "avg",
            label: "Average",
            summaryResult: data.length ? "$" + avg.toFixed(2) : ""
        });
        return result;
    }
}

const result = [];
        result.push(
        {
            key: "min",
            label: "Min",
            summaryResult: IgxNumberSummaryOperand.min(data)
        },
        {
            key: "max",
            label: "Max",
            summaryResult: IgxNumberSummaryOperand.max(data)
        },
        {
          key: "avg",
          label: "Avg",
          summaryResult: IgxNumberSummaryOperand.average(data)
        });
        return result;
    }
}

const result = [];
        result.push(
        {
            key: "min",
            label: "Min",
            summaryResult: IgxNumberSummaryOperand.min(data)
        },
        {
            key: "max",
            label: "Max",
            summaryResult: IgxNumberSummaryOperand.max(data)
        },
        {
          key: "avg",
          label: "Avg",
          summaryResult: IgxNumberSummaryOperand.average(data)
        });
        return result;
    }
}

const result = [];
        result.push(
            {
                key: 'min',
                label: 'Min',
                summaryResult: IgxNumberSummaryOperand.min(data)
            },
            {
                key: 'max',
                label: 'Max',
                summaryResult: IgxNumberSummaryOperand.max(data)
            },
            {
                key: 'avg',
                label: 'Avg',
                summaryResult: IgxNumberSummaryOperand.average(data)
            });
        return result;
    }
}

public operate(data?: any[]): IgxSummaryResult[] {
        const result = [];
        const avg = IgxNumberSummaryOperand.average(data);
        result.push({
            key: "avg",
            label: "Average",
            summaryResult: data.length ? "$" + avg.toFixed(2) : ""
        });
        return result;
    }
}

const result = [];
        result.push(
            {
                key: "min",
                label: "Min",
                summaryResult: IgxNumberSummaryOperand.min(data)
            },
            {
                key: "max",
                label: "Max",
                summaryResult: IgxNumberSummaryOperand.max(data)
            },
            {
                key: "avg",
                label: "Avg",
                summaryResult: IgxNumberSummaryOperand.average(data)
            });
        return result;
    }
}