Session: Querying: How to Stream Query Results

Query results can be streamed using the stream() method from the advanced session operations. The query can be issued using either a static index, or it can be a dynamic one where it will be handled by an auto index.

Syntax

session.advanced.stream(query, [statsCallback], [callback]);

Example I - Using Static Index

const query = session
    .query({ indexName: "Employees/ByFirstName" })
    .whereEquals("FirstName", "Robert");

// stream() returns Node.js Readable 
const stream = await session.advanced.stream(query);

stream.on("data", data => {
    // Employee { FirstName: "Robert", LastName: "Smith" id: "employees/1-A" }
});

stream.on("error", err => {
    // handle errors
});

stream.on("end", () => {
    // stream ended
});

Example II - Dynamic Document Query

const query = session.advanced
    .documentQuery(Employee)
    .whereEquals("FirstName", "Robert");

let streamStats;
const stream = await session.advanced
    .stream(query, stats => streamStats = stats);

stream.on("data", data => {
    // Employee { FirstName: "Robert", LastName: "Smith" id: "employees/1-A" }
});

stream.on("error", err => {
    // handle errors
});

stream.on("end", () => {
    // stream ended
});

Example III - Dynamic Raw Query

const rawQuery = session.advanced
    .rawQuery("from Employees where FirstName = 'Robert'");

const stream = session.advanced.stream(rawQuery);

stream.on("data", data => {
    // Employee { FirstName: "Robert", LastName: "Smith" id: "employees/1-A" }
});

stream.on("error", err => {
    // handle errors
});

stream.on("end", () => {
    // stream ended
});