HEXISTS

Check if a hash field exists

Usage

Returns if field is an existing field in the hash stored at key.

await redis.hexists(key, field);

Parameters

key · string · required

The key of the hash

field · string · required

The field name to check for existence

Response

exists · number

Returns 1 if the hash contains the field, 0 if the hash does not contain the field or the key does not exist.

Examples

Check if a field exists

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

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

// Set hash fields
await redis.hset('user:1000', {
  name: 'Alice',
  email: '[e-mail]'
});

// Check if field exists
const hasName = await redis.hexists('user:1000', 'name');
console.log(hasName); // 1

const hasAge = await redis.hexists('user:1000', 'age');
console.log(hasAge); // 0

Conditional field operations

// Only set a field if it doesn't exist
const exists = await redis.hexists('user:1000', 'defaultTheme');

if (!exists) {
  await redis.hset('user:1000', { defaultTheme: 'light' });
}

Validate required fields

interface RequiredFields {
  name: boolean;
  email: boolean;
  phone: boolean;
}

const checkRequired = async (userId: string): Promise<RequiredFields> => {
  const [hasName, hasEmail, hasPhone] = await Promise.all([
    redis.hexists(`user:${userId}`, 'name'),
    redis.hexists(`user:${userId}`, 'email'),
    redis.hexists(`user:${userId}`, 'phone'),
  ]);

  return {
    name: hasName === 1,
    email: hasEmail === 1,
    phone: hasPhone === 1,
  };
};

const validation = await checkRequired('1000');
console.log(validation); // { name: true, email: true, phone: false }

Check before deletion

// Check if field exists before attempting deletion
if (await redis.hexists('user:1000', 'tempToken')) {
  await redis.hdel('user:1000', 'tempToken');
  console.log('Temporary token removed');
}

Feature flag checking

// Check if a user has a specific feature enabled
const hasFeature = await redis.hexists('user:1000:features', 'betaAccess');

if (hasFeature) {
  console.log('User has beta access');
}

Non-existent key

// Check field on non-existent key
const exists = await redis.hexists('user:9999', 'name');
console.log(exists); // 0

Notes

• Returns 1 (not true) when the field exists
• Returns 0 (not false) when the field doesn’t exist
• Useful for conditional logic before setting or deleting fields
• More efficient than getting the value when you only need to check existence

See Also

• HGET - Get a hash field value
• HSET - Set hash field values
• HDEL - Delete hash fields
• HKEYS - Get all field names in a hash