Node.js NodeJS with Redis Some more important operations supported by node_redis.
Example
Checking the Existence of Keys
Sometimes you may need to check if a key already exists and proceed accordingly. To do so you can use exists() function as shown below:
client.exists('key', function(err, reply) {
if (reply === 1) {
console.log('exists');
} else {
console.log('doesn\'t exist');
}
});
Deleting and Expiring Keys
At times you will need to clear some keys and reinitialize them. To clear the keys, you can use del command as shown below:
client.del('frameworks', function(err, reply) {
console.log(reply);
});
You can also give an expiration time to an existing key as following:
client.set('key1', 'val1');
client.expire('key1', 30);
The above snippet assigns an expiration time of 30 seconds to the key key1.
Incrementing and Decrementing
Redis also supports incrementing and decrementing keys. To increment a key use incr() function as shown below:
client.set('key1', 10, function() {
client.incr('key1', function(err, reply) {
console.log(reply); // 11
});
});
The incr() function increments a key value by 1. If you need to increment by a different amount, you can use incrby() function. Similarly, to decrement a key you can use the functions like decr() and decrby().
