moleike

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) {

moleike

'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;
  }

moleike

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

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!'
  } = {}) {

moleike

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)
        }

moleike

// 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;

moleike

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' } ]

moleike

# -*- 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

moleike

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

moleike

-- 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 ()