How to use the node-opcua-types.BrowseDescription.schema function in node-opcua-types

ReferenceDescription,
    BrowseResult, BrowseDescription, BrowseDescriptionOptions,
    BrowseRequestOptions,
    BrowseNextRequest, BrowseNextResponse, BrowseNextRequestOptions,
    ViewDescription,
    BrowseRequest, BrowseResponse
} from "node-opcua-types";

BrowseResult.schema.fields[1].defaultValue =  null;

BrowseDescription.schema.fields[0].documentation = "The id of the node to browse.";
BrowseDescription.schema.fields[1].documentation = "The direction of the references to return.";
BrowseDescription.schema.fields[2].documentation = "The type of references to return." +
    "Specifies the NodeId of the ReferenceType to follow. Only instances of this ReferenceType or" +
    " its subtype are returned. If not specified then all ReferenceTypes are returned and includeSubtypes is ignored.";
BrowseDescription.schema.fields[3].documentation = "Includes subtypes of the reference type.";
// mask :
//  bit
//   0   Object
//   1   Variable
//   2   Method
//   3   ObjectType
//   4   VariableType
//   5   ReferenceType
//   6   DataType
//   7   View
BrowseDescription.schema.fields[4].documentation =
    "A mask indicating which node classes to return. 0 means return all nodes.";
// mask : (see ResultMask)
//  bit
//   0   ReferenceType
//   1   IsForward

import { NodeClass } from "node-opcua-data-model";

export { BrowseDirection } from "node-opcua-data-model";

export {
    ReferenceDescription,
    BrowseResult, BrowseDescription, BrowseDescriptionOptions,
    BrowseRequestOptions,
    BrowseNextRequest, BrowseNextResponse, BrowseNextRequestOptions,
    ViewDescription,
    BrowseRequest, BrowseResponse
} from "node-opcua-types";

BrowseResult.schema.fields[1].defaultValue =  null;

BrowseDescription.schema.fields[0].documentation = "The id of the node to browse.";
BrowseDescription.schema.fields[1].documentation = "The direction of the references to return.";
BrowseDescription.schema.fields[2].documentation = "The type of references to return." +
    "Specifies the NodeId of the ReferenceType to follow. Only instances of this ReferenceType or" +
    " its subtype are returned. If not specified then all ReferenceTypes are returned and includeSubtypes is ignored.";
BrowseDescription.schema.fields[3].documentation = "Includes subtypes of the reference type.";
// mask :
//  bit
//   0   Object
//   1   Variable
//   2   Method
//   3   ObjectType
//   4   VariableType
//   5   ReferenceType
//   6   DataType
//   7   View
BrowseDescription.schema.fields[4].documentation =