RPOP

Remove and return the last element(s) of a list

Overview

Removes and returns the last element of the list stored at key. When a count is provided, removes and returns up to count elements from the tail of the list.

Method Signature

rpop<TData = string>(key: string): Promise<TData | null>
rpop<TData = string[]>(key: string, count: number): Promise<TData | null>

Parameters

key · string · required

The key of the list.

count · number

The number of elements to pop from the tail. When specified, returns an array of elements instead of a single element.

Return Value

element · TData | null

When called without count: The last element of the list, or null if the list is empty or does not exist.

When called with count: An array of popped elements (from tail to head), or null if the list is empty or does not exist.

Examples

Basic Usage

import { Redis } from '@upstash/redis';

const redis = new Redis({
  url: process.env.UPSTASH_REDIS_REST_URL,
  token: process.env.UPSTASH_REDIS_REST_TOKEN,
});

// Set up a list
await redis.rpush('mylist', 'hello', 'world');
// List is: ['hello', 'world']

// Pop the last element
const element = await redis.rpop('mylist');
console.log(element); // 'world'

// Pop from empty list
const empty = await redis.rpop('nonexistent');
console.log(empty); // null

Pop Multiple Elements

// Set up a list
await redis.rpush('stack', 'first', 'second', 'third', 'fourth');

// Pop multiple elements from the tail
const items = await redis.rpop<string[]>('stack', 2);
console.log(items); // ['fourth', 'third']

Working with Objects

interface Event {
  type: string;
  timestamp: number;
  data: Record<string, any>;
}

// Add events
await redis.rpush<Event>('events', {
  type: 'user.login',
  timestamp: Date.now(),
  data: { userId: '123' },
});

// Pop the most recent event
const event = await redis.rpop<Event>('events');
console.log(event?.type); // 'user.login'

Stack Implementation

// RPUSH and RPOP implement a stack (LIFO)
await redis.rpush('stack', 'A');
await redis.rpush('stack', 'B');
await redis.rpush('stack', 'C');

const third = await redis.rpop('stack');
console.log(third); // 'C'

const second = await redis.rpop('stack');
console.log(second); // 'B'

const first = await redis.rpop('stack');
console.log(first); // 'A'

Recent Items Processing

// Process the most recent items
const recentItems = await redis.rpop<string[]>('recent:activity', 5);

if (recentItems) {
  // Items are ordered from most recent to least recent
  for (const item of recentItems) {
    await processRecentActivity(item);
  }
}

See Also

• LPOP - Remove and return the first element of a list
• RPUSH - Insert elements at the tail of a list
• LRANGE - Get a range of elements from a list
• LLEN - Get the length of a list