forkdb-on-promises.js

var Promise = require('promise');
var concat = require('concat-stream');

module.exports = function(fdb) {

  this.read = function(key){
    return new Promise(function(resolve, reject){
      var headsCS = concat(function(hashes) {
        var readCS = concat(function(buffer){
          resolve(JSON.parse(buffer.toString()));
        }); 
        fdb.createReadStream(hashes[0].hash).pipe(readCS);
      }); 
      fdb.heads(key).pipe(headsCS);
    }); 
  };  

  this.write = function(doc, prev) {
    return new Promise(function(resolve, reject){
      var meta = { key: doc.key };
      if (prev) meta.prev = prev;
      fdb.createWriteStream(meta, function(err, id) {
        if (err) reject(err);
        else resolve(doc);
      }).end(JSON.stringify(doc));
    }); 
  };
};