Populate data on the basis of column type value

Working with Data
,
1

I have created a schema in nodejs which structure is

enum ReportType {
    USER = 'user',
    POST = 'post',
}


const ReportTargetSchema = new Schema<IReportTarget>({
    comment: {
        type: Schema.Types.ObjectId,
        ref: Comments
    },
    report_type_id: {
        type: Schema.Types.ObjectId,
    },
    report_type: {
        type: String,
        enum: ReportType
    }
}, {
    timestamps: true
});

I want to perform a lookup based on the report_type. If the report_type value is ‘user’, then I want to fetch data from the users collection, and if it is ‘post’, then I want to fetch data from the posts collection.