Neo4j JS driver cypher "WHERE" clause not working with parameters

Question

I have a simple function that matches a User to an Id and should create a relationship like this.

const createRelation = (userId: string, todoId: string, relationship: string) => {
    return session.run(
        'MATCH (a:User),(b:Todo)' +
        'WHERE a.id = $userId AND b.id = $todoId' +
        'CREATE (b)-[r:$relationship]->(a)' +
        'RETURN r',
        {
            userId: userId,
            todoId: todoId,
            relationship: relationship,
        }
    );
}

This code does not throw any errors, but it also does not create a relationship. If I set the values for userId and todoId manually, eg to "1" , it works fine! Am I using the parameters wrong? If so, how? (I also already tried setting the relationship type manually, no relationship gets created if I use the parameters.)

Answer 1

Turns out you can't parametrizefor these kinds of constructs.

Parameters cannot be used for the following constructs, as these form part of the query structure that is compiled into a query plan:

• property keys; so, MATCH (n) WHERE n.$param = 'something' is invalid
• relationship types
• labels

I built the string myself like so:

'WHERE a.id = ' + userId + ' AND b.id = ' + todoId +