How to use the node-opcua-data-model.makeAccessLevelFlag function in node-opcua-data-model

function _install_condition_variable_type(
  node: UAConditionVariable
) {
    assert(node instanceof BaseNode);
    // from spec 1.03 : 5.3 condition variables
    // However,  a change in their value is considered important and supposed to trigger
    // an Event Notification. These information elements are called ConditionVariables.
    if (node.sourceTimestamp) {
        node.sourceTimestamp.accessLevel = makeAccessLevelFlag("CurrentRead");
    } else {
        console.warn("cannot find node.sourceTimestamp", node.browseName.toString());
    }
    node.accessLevel = makeAccessLevelFlag("CurrentRead");

    // from spec 1.03 : 5.3 condition variables
    // a condition VariableType has a sourceTimeStamp exposed property
    // SourceTimestamp indicates the time of the last change of the Value of this ConditionVariable.
    // It shall be the same time that would be returned from the Read Service inside the DataValue
    // structure for the ConditionVariable Value Attribute.

    assert(node.typeDefinitionObj.browseName.toString() === "ConditionVariableType");
    assert(node.sourceTimestamp.browseName.toString() === "SourceTimestamp");
    node.on("value_changed", _update_sourceTimestamp);
}

function _install_condition_variable_type(
  node: UAConditionVariable
) {
    assert(node instanceof BaseNode);
    // from spec 1.03 : 5.3 condition variables
    // However,  a change in their value is considered important and supposed to trigger
    // an Event Notification. These information elements are called ConditionVariables.
    if (node.sourceTimestamp) {
        node.sourceTimestamp.accessLevel = makeAccessLevelFlag("CurrentRead");
    } else {
        console.warn("cannot find node.sourceTimestamp", node.browseName.toString());
    }
    node.accessLevel = makeAccessLevelFlag("CurrentRead");

    // from spec 1.03 : 5.3 condition variables
    // a condition VariableType has a sourceTimeStamp exposed property
    // SourceTimestamp indicates the time of the last change of the Value of this ConditionVariable.
    // It shall be the same time that would be returned from the Read Service inside the DataValue
    // structure for the ConditionVariable Value Attribute.

    assert(node.typeDefinitionObj.browseName.toString() === "ConditionVariableType");
    assert(node.sourceTimestamp.browseName.toString() === "SourceTimestamp");
    node.on("value_changed", _update_sourceTimestamp);
}

function _install_condition_variable_type(node) {
    assert(node instanceof BaseNode);
    // from spec 1.03 : 5.3 condition variables
    // However,  a change in their value is considered important and supposed to trigger
    // an Event Notification. These information elements are called ConditionVariables.
    if (node.sourceTimestamp) {
        node.sourceTimestamp.accessLevel = makeAccessLevelFlag("CurrentRead");
    } else {
        console.warn("cannot find node.sourceTimestamp", node.browseName.toString());
    }
    node.accessLevel = makeAccessLevelFlag("CurrentRead");

    // from spec 1.03 : 5.3 condition variables
    // a condition VariableType has a sourceTimeStamp exposed property
    // SourceTimestamp indicates the time of the last change of the Value of this ConditionVariable.
    // It shall be the same time that would be returned from the Read Service inside the DataValue
    // structure for the ConditionVariable Value Attribute.

    assert(node.typeDefinitionObj.browseName.toString() === "ConditionVariableType");
    assert(node.sourceTimestamp.browseName.toString() === "SourceTimestamp");
    node.on("value_changed", _update_sourceTimestamp);
}

public checkPermission(node: BaseNode, action: string): boolean {

        // tslint:disable:no-bitwise
        const lNode = node as any;

        assert(AccessLevelFlag.hasOwnProperty(action));
        const actionFlag: number = makeAccessLevelFlag(action);

        if (!lNode._permissions) {
            return (lNode.userAccessLevel & actionFlag) === actionFlag;
        }

        const permission: string[] = lNode._permissions[action];

        if (!permission) {
            return (lNode.userAccessLevel & actionFlag) === actionFlag;
        }

        const userRole = this.getCurrentUserRole();

        if (userRole === "default") {
            return (lNode.userAccessLevel & actionFlag) === actionFlag;
        }

function convertAccessLevel(accessLevel?: string | null): AccessLevelFlag {
    const accessLevelN: number = parseInt(accessLevel || "1", 10); // CurrentRead if not specified
    return makeAccessLevelFlag(accessLevelN);
}

function adjust_userAccessLevel(userAccessLevel: any, accessLevel: any) {
    userAccessLevel = utils.isNullOrUndefined(userAccessLevel) ? "CurrentRead | CurrentWrite" : userAccessLevel;
    userAccessLevel = makeAccessLevelFlag(userAccessLevel);
    accessLevel = utils.isNullOrUndefined(accessLevel) ? "CurrentRead | CurrentWrite" : accessLevel;
    accessLevel = makeAccessLevelFlag(accessLevel);
    return makeAccessLevelFlag(accessLevel & userAccessLevel);
}

function adjust_userAccessLevel(userAccessLevel: any, accessLevel: any) {
    userAccessLevel = utils.isNullOrUndefined(userAccessLevel) ? "CurrentRead | CurrentWrite" : userAccessLevel;
    userAccessLevel = makeAccessLevelFlag(userAccessLevel);
    accessLevel = utils.isNullOrUndefined(accessLevel) ? "CurrentRead | CurrentWrite" : accessLevel;
    accessLevel = makeAccessLevelFlag(accessLevel);
    return makeAccessLevelFlag(accessLevel & userAccessLevel);
}

function adjust_userAccessLevel(userAccessLevel: any, accessLevel: any) {
    userAccessLevel = utils.isNullOrUndefined(userAccessLevel) ? "CurrentRead | CurrentWrite" : userAccessLevel;
    userAccessLevel = makeAccessLevelFlag(userAccessLevel);
    accessLevel = utils.isNullOrUndefined(accessLevel) ? "CurrentRead | CurrentWrite" : accessLevel;
    accessLevel = makeAccessLevelFlag(accessLevel);
    return makeAccessLevelFlag(accessLevel & userAccessLevel);
}