Leaderboard

Leaderboard backed by Redis in Node.js.

Installation

$ npm install redis-leaderboard

API

#Constructor

var lb = new Leaderboard('name', [options], [redisOptions|redisClient])

Creates a new leaderboard or attaches to an existing leaderboard.

###Options

• pageSize - default: 0

  Page size to be used when paging through the leaderboard.

• reverse - default: false

  If true various methods will return results in lowest-to-highest order.

##Methods

• add(member, score, [λ])

  Ranks a member in the leaderboard.

  lb.add('raheem', 100, function(err) {
    // no arguments except err
  });

• incr(member, score, [λ])

  Increments the score of a member by provided value and ranks it in the leaderboard. Decrements if negative.

  lb.incr('raheem', 2, function(err) {
    // no arguments except err
  });

  now the score to the member raheem would be 102.

• rank(member, λ)

  Retrieves the rank for a member in the leaderboard.

  lb.rank('raheem', function(err, rank) {
    // rank - current position, -1 if a member doesn't
    // fall within the leaderboard
  });

• score(member, λ)

  Retrieves the score for a member in the leaderboard.

  lb.score('raheem', function(err, score) {
    // score - current score, -1 if a member doesn't
    // fall within the leaderboard
  });

• list([page], λ)

  Retrieves a page of leaders from the leaderboard.

  lb.list(function(err, list) {
    // list - list of leaders are ordered from
    // the highest to the lowest score
    // [
    //   {member: 'member1', score: 30},
    //   {member: 'member2', score: 20},
    //   {member: 'member3', score: 10}
    // ]
  });

• at(rank, λ)

  Retrieves a member on the spicified ranks.

  lb.at(2, function(err, member) {
    // member - member at the specified rank i.e who has 2nd rank,
    // null if a member is not found
    // {
    //   member: 'member1',
    //   score: 30
    // }
  });

• rm(member, [λ])

  Removes a member from the leaderboard.

  lb.rm('raheem', function(err, removed) {
    // removed - false in case the removing member 
    // doesn't exist in the leaderboard.
    // true - successful remove
  });

• total([λ])

  Retrieves the total number of members in the leaderboard.

  lb.total(function(err, number) {
    // captain obvious
  });

• rangevalue(min, max, options, [λ])

  Returns the number of elements in the sorted set at key with a score between min and max.

  var options = {
    a:"exclusive",
    b:"inclusive"
  }
  
  lb.rangevalue(90,110,options,function(err,number){
      // returns a number -- how many records in between score 91 (here 90 exclusive) to 110
      // returns 0 if no records found
  })

• rangeByScoreInfo(min, max, options, [λ])

  Returns all the elements in the sorted set at key with a score between min and max.

  var options = {
    a:"exclusive",
    b:"inclusive"
  }
  
  lb.rangeByScoreInfo(90,110,options,function(err,number){
      // returns all records in between score 91 (here 90 exclusive) to 110
      // returns null if no records found
  })

• removeRangeByRank(min, max, [λ])

   Removes all elements in the sorted set stored at key with rank between min rank and max rank. min rank starts from 0.
  
   lb.removeRangeByRank(0,2,function(err,number){
       // returns number of records removed if true
       // returns 0 if no records removed
   })

• removeRangeByScore(min, max, options, [λ])

  Removes all elements in the sorted set stored at key with a score between min and max.

   var options = {
     a:"exclusive",
     b:"inclusive"
   }
  
   lb.removeRangeByScore(90,110,options,function(err,number){
       // remove all records in between score 91 (here 90 exclusive) to 110
       // returns null if no records found
   })

• getScoreByPattern(pattern, [λ])

   scan in the sorted set for matching pattern and retrieve all matching records.
  
   var pattern = "rah"
  
   lb.getScoreByPattern(pattern,function(err,number){
        //return matching elements in array
        //[{member : "raheem",score:100},{member:"raheja",score:110}]
        //return empty array if no records match
  
   })

License

MIT. Copyright (c) 2015 raheemmujavar <[email protected]>

Author: raheemmujavar