'NodeJS and Redis : getting three values simultaneously

currently I do this for getting many values in NodeJS and Redis with node-redis :

redis.get('data1', function(err, data1)
{ 
     redis.get('data2', function(err, data2)
     {
         redis.get('data3', function(err, data3)  
         {

              if (data3 == xx && data2 == xx && data3 == xx)
              { 
                  console.log('its ok'); 
              }

          });
      });
});

The problem is that the three request will be one after another, I want to make 3 at once, and then call my condition like this for example (this don't work it's just for you understand what I want) :

redis.get('data1', function(err, data1) { var data1 = data1; });
redis.get('data2', function(err, data2) { var data2 = data2; });
redis.get('data3', function(err, data3) { var data3 = data3; });
// When the 3 get operations was finished 
if (data3 == xx && data2 == xx && data3 == xx)
{ 
    console.log('its ok'); 
}

Thank you in advance

node.jsredisgetnode-redis


Solution 1:[1]

MGET will probably be the fastest, instead of going back and forth 3 times:

client.mget(["data1", "data2", "data3"], function (err, res) {
    console.dir(res);
});

Solution 2:[2]

One of the possible (but rather popular) ways is to use the async module like so:

async.map(['data1','data2','data3'], redis.get, function (err, results) {
  if (err) { return; }
  // results is now an array
});

Solution 3:[3]

Small update, maybe it will help someone avoid some frustration - in node-redis v4 some non-backwards compatible changes were implemented and, for example, .mget method has been changed to .mGet. See eg:
https://github.com/redis/node-redis/issues/1765
https://github.com/redis/node-redis/releases

Also now methods return Promises by default so async/await can be used instead of callbacks:

async testFunc() {
    const values = ["first", "some", "second", "test", "third", "values"];
    const mSetResult = await client.mSet(values);
    console.log(mSetResult); // OK
    const mGetResult = await client.mGet(["first", "second", "fourth", "third"]);
    console.log(mGetResult); // [ 'some', 'test', null, 'values' ]
}

await testFunc();

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 Ofir Luzon
Solution 2
Solution 3 Zuku

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