jkdb

A zero dependency javascript Node.js package to interface with kdb+/q (v2.6+).

Installation

npm install --save-dev jkdb

Quick Start

Connect to a q Process

const { QConnection } = require("jkdb");
const q = new QConnection({ port: 1800 });
q.connect((err) => {
  if (err) throw err;
  console.log("connected");
  // send query from here
});

Connect to a TLS-protected q Process

const { QConnection } = require("jkdb");
const q = new QConnection({ port: 1800, useTLS: true });
q.connect((err) => {
  if (err) throw err;
  console.log("connected");
  // send query from here
});

Connect to a q Process with Credentials

const { QConnection } = require("jkdb");
const q = new QConnection({ port: 1800, user: "user", password: "password" });
q.connect((err) => {
  if (err) throw err;
  console.log("connected");
  // send query from here
});

Send a Sync Query

q.sync("(+/) til 10", (err, res) => {
  if (err) throw err;
  console.log("result: ", res);
  // result: 45
});

Send a Sync Function Call

q.sync(["(*/)", [22, 27, 45]], (err, res) => {
  if (err) throw err;
  console.log("result: ", res);
  // result: 26730
});

Send a Sync Function Call with Multiple Parameters

q.sync(
  [
    "mmu",
    [1, 2, 3],
    [
      [1, 2, 3],
      [4, 5, 6],
      [7, 8, 9],
    ],
  ],
  (err, res) => {
    if (err) throw err;
    console.log("result: ", res);
    // result: 30,36,42
  }
);

Send an Async Query

q.asyn("show 99", (err) => {
  if (err) throw err;
});

Send an Async Function Call

q.asyn(["show", 99], (err) => {
  if (err) throw err;
});

Subscribe

q.on("upd", (table, data) => {
  console.log(table, data);
});

q.sync(".u.sub[`trade;`7203.T]", (err, _res) => {
  if (err) throw err;
});

Close q Connection

q.close(() => {
  console.log("closed");
});

Date Types

Deserialization

Deserialization of long and timestamp can be controlled by QConnection arguments useBigInt and includeNanosecond.

| k type | argument | javascript type | k null | infinity | -infinity | | ---------- | ----------------- | --------------- | -------------------------------- | -------- | --------- | | boolean | | Boolean | | | | | guid | | String | 00000000000000000000000000000000 | | | | byte | | Number | | | | | short | | Number | NaN | Infinity | -Infinity | | int | | Number | NaN | Infinity | -Infinity | | long | | Number | NaN | Infinity | -Infinity | | long | useBigInt | BigInt | NaN | Infinity | -Infinity | | real | | Number | NaN | Infinity | -Infinity | | float | | Number | NaN | Infinity | -Infinity | | char | | String | ' ' | | | | symbol | | String | '' | | | | timestamp | | Date | null | null | null | | timestamp | includeNanosecond | String | '' | '' | '' | | month | | String | null | null | null | | date | | Date | null | null | null | | date | dateToMillisecond | Number | NaN | Infinity | -Infinity | | datetime | | Date | null | null | null | | datetime | dateToMillisecond | Number | NaN | Infinity | -Infinity | | timespan | | String | null | null | null | | minute | | String | null | null | null | | second | | String | null | null | null | | time | | String | null | null | null | | dict | | Object | | | | | list | | Array | | | | | table | | Object | | | | | lambda | | String | | | | | projection | | Array | | | |

Serialization

Atom

| javascript type | k type | | --------------- | --------- | | Boolean | boolean | | Number | float | | String | chars | | Date | timestamp |

Array

| javascript type | Symbol.for('kType') | k type | | --------------- | ------------------- | --------- | | Boolean Array | b | boolean | | String Array | g | guid | | Number Array | i | int | | Number Array | j | long | | Number Array | f | float | | String Array | c | char | | String Array | s | symbol | | Date Array | p | timestamp | | Date Array | d | date | | Date Array | z | datetime |

Use Symbol.for('kType') to specify k type for the array, e.g.

const ints = [99, 11, 3, 3];
ints[Symbol.for("kType")] = "j";

Object without meta

Convert to a dictionary, keys are symbols, e.g.

const dict = { sym: "8306.T", price: 668.2 };

Object with meta

Convert to a table, e.g.

const table = {
  sym: ["AXJO", "AXJO"],
  date: [new Date("2021-05-13"), new Date("2021-05-14")],
  open: [7000, 6000],
};
table[Symbol.for("meta")] = {
  c: ["sym", "date", "open"],
  t: ["s", "d", "f"],
};