Alexandre Moreno moleike

ES6 Defaults / Overrides Pattern

Combine default parameters and destructuring for a compact version of the defaults / overrides pattern.

function foo ({
    bar = 'no',
    baz = 'works!'
  } = {}) {

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

	import express from "express";

	/**
	* Takes a route handling function and returns a function
	* that wraps it after first checking that the strings in
	* `reserved` are not part of `req.body`. Used for ensuring
	* create and update requests do not overwrite server-generated
	* values.
	*/
	function checkReservedParams(routeHandler, ...reserved) {

	'use strict';
	const statusCodes = require('http').STATUS_CODES;

	function createError(code, name) {
	return function(message) {
	Error.captureStackTrace(this, this.constructor);
	this.name = name;
	this.message = message;
	this.statusCode = code;
	}

	function delay(expressionAsFunction) {
	var result;
	var isEvaluated = false;

	return function () {
	if (!isEvaluated)
	result = expressionAsFunction();
	return result;
	};
	}

	var util = require('util')

	function hook_stdout(callback) {
	var old_write = process.stdout.write

	process.stdout.write = (function(write) {
	return function(string, encoding, fd) {
	write.apply(process.stdout, arguments)
	callback(string, encoding, fd)
	}

	// reverse proxy (HTTP(s) to LWM2M over MQTT)
	// this should be mounted on an Express app

	const router = require('express').Router()
	const shepherd = require('lib/shepherd');
	const ch = require('lib/status'); // coap to http status
	const herrero = require('herrero');
	const bodyParser = require('body-parser')
	const { NotFoundError } = herrero;

	const parseAttributes = payload => payload
	.split(',')
	.map(pair => pair.split('='))
	.filter(pair => pair.length === 2)
	.map(([key,val]) => ({ [key]: val }))

	// > parseAttributes('pmin=5,pmax=40')
	// [ { pmin: '5' }, { pmax: '40' } ]

	# -- coding: utf-8 --

	import numpy as np
	import matplotlib.pyplot as plt
	import scipy.integrate as integrate

	# Dimension of image in pixels
	N = 256
	# Number of samples to use for integration
	M = 32

	-- randomized quick sort with 3-way partition
	module QuickSort (quicksort) where
	import Data.Array.ST
	import Control.Monad
	import Control.Monad.ST
	import System.Random

	type QA s = STUArray s Int Int

	swap :: Int -> Int -> QA s -> ST s ()