Description
Returns the remaining time to live of a key that has a timeout. This introspection capability allows a Redis client to check how many seconds a given key will continue to be part of the dataset.
Method Signature
ttl(key: string): Promise<number>
Parameters
The key to get the time to live for
Return Value
The time to live in seconds, or:
-2 if the key does not exist-1 if the key exists but has no associated expire
Examples
Get TTL for a key with expiration
await redis.set("mykey", "value");
await redis.expire("mykey", 100);
const ttl = await redis.ttl("mykey");
console.log(ttl); // ~100 (depends on timing)
Key with no expiration
await redis.set("mykey", "value");
const ttl = await redis.ttl("mykey");
console.log(ttl); // -1
Non-existent key
const ttl = await redis.ttl("nonexistent");
console.log(ttl); // -2
Monitor TTL over time
await redis.set("mykey", "value");
await redis.expire("mykey", 60);
const ttl1 = await redis.ttl("mykey");
console.log(ttl1); // ~60
// Wait some time...
setTimeout(async () => {
const ttl2 = await redis.ttl("mykey");
console.log(ttl2); // Less than ttl1
}, 5000);
See Also
- expire - Set a key’s time to live
- persist - Remove the expiration from a key