Firebase game matching algorithm -

i'm trying create player matching algorithm. expected work that:

algorithm:

1. player creates game request specifying bet , gametype.
2. server subscribes following query list:

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{   'gamerequests': {     '1': {       createdat: 1454777718074,       uid: 123,       bet: 10,       gametype: 'nhl'     },     '2': {       createdat: 1454777718075,       uid: 123,       bet: 20,       gametype: 'nhl'     },     '3': {       createdat: 1454777718076,       uid: 321,       bet: 10,       gametype: 'nhl'     },   } } 

i requests keys '1', '3'.

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3. now delete children keys '1', '3' , create game them.

what have:

so far i'm doing loading whole gamerequests branch.

randomgamesref.on('value', ongamerequestsupdate)  function ongamerequestsupdate (snapshot) {     const gamerequests = snapshot.val()      const pairs = _.chain(gamerequests)       // transform array       .values()        // group sport , bet size       .groupby((req) => req.gametype + '+' + req.bet)        // map groups pairs       .map((group) => {         return _.chain(group)           .uniqby('createdby')           .take(2)           .value()       })       .filter((pairs) => pairs.length === 2)       .value()      // having pairs can delete them      // database , create new game   } 

but loading memory every time doesn't seem idea.

question: how implemented in firebase?

in nosql end modeling data way want access in code. instead of reading game requests , grouping them gametype , bet in code, consider storing them under key combines gametype , bet:

{   'gamerequests': {     'nhl_10': {       '1': {         createdat: 1454777718074,         uid: 123,       },       '3': {         createdat: 1454777718076,         uid: 321,       }     },     'nhl_20': {       '2': {         createdat: 1454777718075,         uid: 123,       }     }   } } 

now code becomes:

function ongamerequestsupdate (snapshot) {    snapshot.foreach(function(gametypesnapshot) {      if (gametypesnapshot.numchildren() >= 2) {        // there @ least 1 request pair game type      }    }); }; 

i keep recommending people read this article, since explains nosql data modeling techniques such one.