Insert array into redis from NodeJS

Question

I have an array which I fill up in a for like this:

var obj = [];
for(i = 0; i < data.bids.length; i += 1) {
 obj.push(JSON.parse(data.bids[i][0]));
}

After that I verify if the array contains the desired values (it contains):

console.log("Array after the for: \n");
console.log(obj);

I try to save this under a redis key, but the reply is undefined

client.set('order-book:buy:bitstamp', obj, function(err, reply) {
 console.log(reply);
});

I've also tried with rpush, but no luck.
What could be the problem?

• generalhenry: Did you check err? .set expects a string, it looks like you want client.set(key, JSON.stringify(obj), function (err, reply) { if (err) { console.error(err); } console.log(reply); });
• generalhenry: client.rpush(key, array, callback) is likely what you'll end up with since list is the more natural data type for your data, it'll fail if the key is already set to some other data type (string if you used a set)
• Fogarasi Norbert: It worked with JSON.stringify, if I use rpush I get undefined.

Answer 1

You can check here which types are compatible as redis values data-types-intro.

If you need to save array of objects in redis, the only way to do this is by using JSON.stringify(obj). So in your example it would look something like:

const redisValue = JSON.stringify(obj);
client.set('order-book:buy:bitstamp', redisValue, function(err, reply) {
 console.log(reply);
});

When reading data from redis you can easily use JSON.parse(redisResponse).