Redis: get element from JSON array by index

Question

The package I'm using is redis. I used the following command to store a JSON array in Redis:

await redisClient.json.set('car.volume.tire', '$', []);
await redisClient.json.arrAppend('car.volume.tire', '$', { hello: 'there' });

But when I want to retrieve the element by index, I receive null:

await redisClient.json.get(`car.volume.tire[0]`);

However, the following returns the full JSON array:

await redisClient.json.get(`car.volume.tire`);

What am I doing wrong?

Answer 1

Try:

await redisClient.json.get('car.volume.tire', { path: ['[0]'] });

or you can pass path as just a string as Guy Royse suggested:

await redisClient.json.get('car.volume.tire', { path: '[0]' });

See: "Retrieving JSON Documents from Redis"

---

Full example

import dotenv from "dotenv";
import { createClient } from "redis";

dotenv.config();

const { REDIS_HOST, REDIS_PORT } = process.env;

const redisClient = createClient({
  socket: {
    host: REDIS_HOST,
    port: REDIS_PORT,
  },
});

redisClient.on("error", (err) => console.log("Redis Server Error", err));

await redisClient.connect();

await redisClient.json.set("car.volume.tire", "$", []);
await redisClient.json.arrAppend("car.volume.tire", "$", { hello: "there" });

const found = await redisClient.json.get("car.volume.tire", { path: "[0]" });

console.log(found); // { hello: 'there' }

redisClient.disconnect();