index.js

var level = require('level');
var query = require('level-queryengine');
var fulltext = require('fulltext-engine');
var rimraf = require('rimraf').sync;

rimraf(__dirname + '/db');

var db = query(level(__dirname + '/db', {
  valueEncoding: 'json'
}));

db.query.use(fulltext());
db.ensureIndex('name', 'fulltext', fulltext.index());

var values = Math.pow(26, 3);

var ops = [];

for (var i = 0; i < 26; i++) {
  for (var j = 0; j < 26; j++) {
    for (var k = 0; k < 26; k++) {
      var name = String.fromCharCode(97 + i)
        + String.fromCharCode(97 + j)
        + String.fromCharCode(97 + k);
      ops.push({ type: 'put', key: name, value: { name: name } });
    }
  }
}

ops.push({ type: 'put', key: 'dog training', value: { name: 'dog training' } });
ops.push({ type: 'put', key: 'dog food', value: { name: 'dog food' } });
ops.push({ type: 'put', key: 'who let the dogs out', value: { name: 'who let the dogs out' } });
ops.push({ type: 'put', key: 'cat training', value: { name: 'cat training' } });
ops.push({ type: 'put', key: 'cat food', value: { name: 'cat food' } });
ops.push({ type: 'put', key: 'who let the cats out', value: { name: 'who let the cats out' } });

var start = Date.now();

db.batch(ops, function(err) {
  setTimeout(function () {
    console.log('inserted %s values (took %sms)', values, Date.now() - start);
    if (err) throw err;

    var matches = [];
    var query = 'training';
    console.log('querying for %s', query);
    start = Date.now();

    db.query('name', query)
    .on('data', function(name) {
      console.log(name);
      matches.push(name);
    })
    .on('stats', console.log)
    .on('end', function() {
      console.log('%s out of %s names match (took %sms)',
        matches.length, values, Date.now() - start);
    });
  }, 1000);
});