HSTRLEN command in Redis is used to get the length of the value of a field in a hash stored at key. In Node, it's primarily used when you need to check the size of a particular value of a field without retrieving the entire value.
Let's consider an example where we have a user profile stored in a Redis hash, and we want to know the length of the user's bio description without retrieving the complete data.
In this example, we're setting the bio field for user with id 1000 as 'Software Engineer at XYZ co.' and then checking its length using
hstrlen. The result would be 28 since that's the length of the string.
HSTRLENonly when you need the length of a large string value in a hash. Using
HSTRLENreturns 0 if the field or key does not exist. Make sure the key and field exists in the hash before calling
HSTRLENwill return the length of the string as stored by Redis, not the size in memory.
Q: What if the key or field does not exist in the hash?
A: If the key or field does not exist,
HSTRLEN returns 0.
HSTRLEN count multi-byte characters correctly?
HSTRLEN counts each character accurately regardless of whether they are single or multi-byte.