Leaderboard-new NPM

Leaderboard

Leaderboard backed by Redis in Node.js.

Installation

$ npm install leaderboard-new

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

 })