Most Used Redis Operations (with Node.js examples)

Using the ioredis library (npm install ioredis):

import Redis from "ioredis";
const redis = new Redis(); // connects to localhost:6379

String Operations

// SET & GET
await redis.set("name", "Alice");
const name = await redis.get("name"); // "Alice"

// SET with expiry (TTL in seconds)
await redis.set("session", "abc123", "EX", 3600); // expires in 1 hour

// SET only if not exists
await redis.setnx("lock", "1");

// Increment / Decrement
await redis.set("counter", 0);
await redis.incr("counter");        // 1
await redis.incrby("counter", 5);   // 6
await redis.decr("counter");        // 5

// Delete a key
await redis.del("name");

// Check if key exists
const exists = await redis.exists("name"); // 0 or 1

// Get TTL
const ttl = await redis.ttl("session"); // seconds remaining

// Set TTL on existing key
await redis.expire("name", 60);

Hash Operations (like objects/maps)

// Set single field
await redis.hset("user:1", "name", "Alice");

// Set multiple fields
await redis.hset("user:1", { name: "Alice", age: "30", city: "NYC" });

// Get single field
const name = await redis.hget("user:1", "name"); // "Alice"

// Get all fields
const user = await redis.hgetall("user:1"); // { name: "Alice", age: "30", ... }

// Delete a field
await redis.hdel("user:1", "city");

// Check if field exists
const exists = await redis.hexists("user:1", "name"); // 0 or 1

List Operations (ordered, allows duplicates)

// Push to left / right
await redis.lpush("tasks", "task1");
await redis.rpush("tasks", "task2", "task3");

// Pop from left / right
const first = await redis.lpop("tasks"); // "task1"
const last  = await redis.rpop("tasks"); // "task3"

// Get range (0 = first, -1 = last)
const all = await redis.lrange("tasks", 0, -1);

// Length
const len = await redis.llen("tasks");

Set Operations (unique values, unordered)

// Add members
await redis.sadd("tags", "nodejs", "redis", "backend");

// Remove member
await redis.srem("tags", "backend");

// Get all members
const tags = await redis.smembers("tags"); // ["nodejs", "redis"]

// Check membership
const isMember = await redis.sismember("tags", "redis"); // 1

// Set size
const size = await redis.scard("tags");

// Intersection / Union / Difference
await redis.sadd("setA", "a", "b", "c");
await redis.sadd("setB", "b", "c", "d");
const inter = await redis.sinter("setA", "setB"); // ["b", "c"]
const union = await redis.sunion("setA", "setB"); // ["a","b","c","d"]
const diff  = await redis.sdiff("setA", "setB");  // ["a"]

Sorted Set Operations (unique values + score)

// Add with score
await redis.zadd("leaderboard", 100, "Alice");
await redis.zadd("leaderboard", 200, "Bob");
await redis.zadd("leaderboard", 150, "Carol");

// Get rank (0-indexed, low to high)
const rank = await redis.zrank("leaderboard", "Alice"); // 0

// Get range by rank (low to high)
const bottom = await redis.zrange("leaderboard", 0, -1); // ["Alice","Carol","Bob"]

// Get range with scores
const withScores = await redis.zrange("leaderboard", 0, -1, "WITHSCORES");

// Get range high to low
const top = await redis.zrevrange("leaderboard", 0, 2);

// Get score of a member
const score = await redis.zscore("leaderboard", "Bob"); // "200"

// Remove member
await redis.zrem("leaderboard", "Alice");

Pub/Sub

const sub = new Redis();
const pub = new Redis();

// Subscribe
sub.subscribe("news", (err, count) => {
  console.log(`Subscribed to ${count} channels`);
});

sub.on("message", (channel, message) => {
  console.log(`[\({channel}]: \){message}`);
});

// Publish
await pub.publish("news", "Hello World!");

Atomic Multi/Exec (Transaction)

const results = await redis
  .multi()
  .set("a", 1)
  .incr("a")
  .get("a")
  .exec();
// results: [["OK"], [2], ["2"]]

Scan (safe alternative to KEYS * in production)

// Iterate all keys matching a pattern
let cursor = "0";
do {
  const [nextCursor, keys] = await redis.scan(cursor, "MATCH", "user:*", "COUNT", 100);
  cursor = nextCursor;
  console.log(keys);
} while (cursor !== "0");