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type PropertyNames<T> = keyof T
type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>
type Filtered<T, C> = { [K in keyof T]: T[K] extends C ? K : never }[keyof T]

class ConfigurationPageContext<T> {
	addTextSetting<K extends PropertyNames<T>>(
		field: Extract<K, Filtered<T, string>>,
		title: string,
		defaultValue: string = null
	): ConfigurationPageContext<Omit<T, K>> {

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Common Math Symbols in Unicode

• Wikipedia - Mathematical operators and symbols in Unicode
• Toptal - HTML Math Symbols, Math Entities and ASCII Math Character Code Reference

Logic

• ¬
• ∧
• ∨

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  ZigZag-Encoding
  ---------------
  
  Maps negative values to positive values while going back and
  forth (0 = 0, -1 = 1, 1 = 2, -2 = 3, 2 = 4, -3 = 5, 3 = 6 ...)

  (i >> bitlength-1) ^ (i << 1)

  with "i" being the number to be encoded, "^" being
  XOR-operation and ">>" would be arithemtic shifting-operation

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/*****************************************************************************
 *                QuantCup 1:   Price-Time Matching Engine
 *
 * Submitted by: voyager
 * 
 * Design Overview:
 *   In this implementation, the limit order book is represented using 
 *   a flat linear array (pricePoints), indexed by the numeric price value. 
 *   Each entry in this array corresponds to a specific price point and holds 
 *   an instance of struct pricePoint. This data structure maintains a list 

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List of Cryptocurrency exchanges with Websocket API

• binance

• bitfinex

• bittrex

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Neo4j directed path through multiple relationships with property filter

From Stackoverflow Question

Being new to Cypher and Neo4j, I am having trouble constructing my query for my use-case. I am building a simple ACL (access control list) and am looking for a path through permission relationships an up a hierarchy as well. A picture may better explain it:

Key:

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package main

import (
	"fmt"
)

type MyEmitter map[string]chan string

func main() {
	myEmitter := MyEmitter{}

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-- show running queries (pre 9.2)
SELECT procpid, age(clock_timestamp(), query_start), usename, current_query 
FROM pg_stat_activity 
WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%' 
ORDER BY query_start desc;

-- show running queries (9.2)
SELECT pid, age(clock_timestamp(), query_start), usename, query 
FROM pg_stat_activity 
WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%' 

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import React, { useReducer, useEffect, useRef } from 'react';
import firebase from 'firebase/app';
import equal from 'deep-equal';

function filterKeys(raw, allowed) {
  if (!raw) {
    return raw;
  }
  let s = new Set(allowed);
  return Object.keys(raw)

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WAL-G PITR

This gist summarises a way to simulate point-in-time recovery (PITR) using WAL-G. Most of the material is adapted from Creston's tutorial.

Setup

First we initialize a database cluster

pg_ctl init -D cluster