should the driver marshal iterable to array?

[jasperblues]

send(): Promise<number> {
    return new Promise((resolve, reject) => {
        this.profiles()
            .then(profiles => Promise.all(profiles.map(it => this.sendWelcomeMail(it))))
            .then(users => {
                const params = {ids: users.map(it => it.id)};
                console.log('Got params: ' + JSON.stringify(params));
                return db.writeQueryAsync(`match (n:CandidateProfile) where n.id in {ids} 
                    set n.hasBeenWelcomed = true return count(n)`, params);
            })
            .then(result => resolve(result.data[0]))
            .catch(err => reject(err));
    });
}

Running the following code results in a parameters argument as follows:

{"ids":["a42b470b-5e19-4fce-934c-d9a634ac21d3","7c1e3d84-389f-481c-944e-efc2f7d76dad","5b8af43a-730f-482e-b7fe-5e6fbf9e91ee","ff1c33f1-fd98-4115-84b2-3780b425cb04","48023149-b8ee-4e34-be42-a4cae5d2b41e","063fed6c-b34b-4600-a043-0112c9eb87fd","d43037d8-e490-485b-b0b3-3ffb4c5df96d","3a113529-81df-4858-a1fd-8e7b4e5354e9","0353642d-e543-45db-8fdd-061a9b660c02","a9c9c34d-9b25-4a2b-b92d-547fc8b309b1"]}

The argument looks identical to me using either es6 or bluebird promise implementation, however with es6, an error is thrown:

Neo4jError: Property values can only be of primitive types or arrays thereof
    at new Neo4jError (/Users/jblues/vampr/vend_node/node_modules/neo4j-driver/lib/v1/error.js:76:132)
    at newError (/Users/jblues/vampr/vend_node/node_modules/neo4j-driver/lib/v1/error.js:66:10)
    at Connection._handleMessage (/Users/jblues/vampr/vend_node/node_modules/neo4j-driver/lib/v1/internal/connector.js:355:56)
    at Dechunker.Connection._dechunker.onmessage (/Users/jblues/vampr/vend_node/node_modules/neo4j-driver/lib/v1/internal/connector.js:286:12)
    at Dechunker._onHeader (/Users/jblues/vampr/vend_node/node_modules/neo4j-driver/lib/v1/internal/chunking.js:246:14)
    at Dechunker.AWAITING_CHUNK (/Users/jblues/vampr/vend_node/node_modules/neo4j-driver/lib/v1/internal/chunking.js:199:21)
    at Dechunker.write (/Users/jblues/vampr/vend_node/node_modules/neo4j-driver/lib/v1/internal/chunking.js:257:28)
    at NodeChannel.self._ch.onmessage (/Users/jblues/vampr/vend_node/node_modules/neo4j-driver/lib/v1/internal/connector.js:259:27)
    at TLSSocket.<anonymous> (/Users/jblues/vampr/vend_node/node_modules/neo4j-driver/lib/v1/internal/ch-node.js:308:16)
    at emitOne (events.js:115:13)

Not sure if this is helpful in its own right, will try to extract a public repo that demonstrates the problem asap.

[jasperblues]

Ah, adding Array.from(users.map(it => it.id)) works. Is it reasonable then to have the driver marshal iterable to an array?

[lutovich]

Hi @jasperblues,

I suppose driver could convert iterables to arrays. There is a possibility that given iterable is infinite which will make driver fail with OOM. Not sure if this is a real problem or no. Will create a card for us to investigate this.

[jasperblues]

Awesome, looking forward to hear the outcome.