make kappa-core views over leveldb
var kappa = require('kappa-core') var View = require('kappa-view-level') var ram = require('random-access-memory') var memdb = require('memdb') var core = kappa(ram, { valueEncoding: 'json' }) var lvl = memdb() var view = View(lvl, { map: function (msg) { return [ [ msg.value.key, msg.value.value ] // map first element to second element ] }, api: { get: function (core, key, cb) { lvl.get(key, cb) } } }) core.use('mapper', view) core.writer(function (err, feed) { feed.append({key: 'foo', value: 'bar'}) feed.append({key: 'bax', value: 'baz'}) core.ready('mapper', function () { core.api.mapper.get('foo', console.log) core.api.mapper.get('bax', console.log) core.api.mapper.get('nix', console.log) }) })outputs
null 'bar' null 'baz' NotFoundError: Key not found in database [nix] var View = require('kappa-view-level')Expects a LevelUP or LevelDOWN instance leveldb.
Required opts are:
map: function (msg): a mapper function that returns an array of[key, value]arrays.api: {}: an object that defines API functions that the view exposes. These can have whatever names you want, be sync or async, and return whatever you'd like.
With npm installed, run
$ npm install kappa-view-level kappa-view-level was inspired by flumeview-level.
ISC
