node-postgres/packages/pg-query-stream/test/fast-reader.js

var assert = require('assert');
var helper = require('./helper');
var QueryStream = require('../');

helper('fast reader', function (client) {
  it('works', function (done) {
    var stream = new QueryStream('SELECT * FROM generate_series(0, 200) num', []);
    var query = client.query(stream);
    var result = [];
    stream.on('readable', function () {
      var res = stream.read();
      while (res) {
        if (result.length !== 201) {
          assert(res, 'should not return null on evented reader');
        } else {
          // a readable stream will emit a null datum when it finishes being readable
          // https://nodejs.org/api/stream.html#stream_event_readable
          assert.equal(res, null);
        }
        if (res) {
          result.push(res.num);
        }
        res = stream.read();
      }
    });
    stream.on('end', function () {
      var total = result.reduce(function (prev, cur) {
        return prev + cur;
      });
      assert.equal(total, 20100);
      done();
    });
    assert.strictEqual(query.read(2), null);
  });
});