Added a basic solution based on level-sublevel.

problems/queue/setup.js

@@ -0,0 +1,7 @@
+
+function setup(run, callback) {
+ console.log(arguments)
+}
+
+module.exports = setup
+module.exports.async = true

problems/queue/solution.js

@@ -0,0 +1,45 @@
+var sublevel = require('level-sublevel')
+
+function Queue(db, name) {
+ if (!(this instanceof Queue)) return new Queue(db, name)
+
+ this._db = sublevel(db).sublevel(name)
+}
+
+module.exports = Queue
+
+Queue.prototype.push = function(element, callback) {
+ var key = (new Date()).toISOString()
+
+ this._db.put(key, element, callback)
+
+ return this;
+}
+
+Queue.prototype.shift = function(callback) {
+ var stream = this._db.createReadStream({
+ limit: 1
+ })
+
+ , db = this._db
+
+ stream.once('data', function(data) {
+ db.del(data.key, function(err) {
+ callback(err, data.value)
+ })
+ })
+
+ stream.once('error', callback)
+
+ return this;
+}
+
+Queue.prototype.clear = function(callback) {
+ this._db.createReadStream()
+ .pipe(this._db.createWriteStream({
+ type: 'del'
+ }))
+ .on('close', callback)
+
+ return this;
+}