jkdb

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, enableTLS: 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", (msg) => {
  console.log(msg);
});

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

Close q Connection

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

Promise API

All connection methods have Promise-based variants for use with async/await.

Connect, Query and Close

const { QConnection } = require("jkdb");
const q = new QConnection({ port: 1800 });

await q.connectAsync();
const res = await q.syncAsync("(+/) til 10");
console.log("result: ", res);
// result: 45
await q.closeAsync();

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"],
};