spion

Second example at

https://www.joyent.com/developers/node/design/errors

in the section "(Not) handling programmer errors"

A database (or other) connection may be leaked, reducing the number of future requests you can handle in parallel. This can get so bad that you're left with just a few connections, and you end up handling requests in series instead of concurrently.

Ok, so I have code that opens a connection, runs a query, then processes the results.

spion

Part 1: Why bubbling is good

We start with the following code

function startListening(server, cb) {
  server.listen(99999, 'localhost', cb)
}

spion

24840 % node skynet.js
499999500000
regular: 378.414ms
499999500000
warmed-up: 262.341ms

spion

Relationship between ES6 and TypeScript modules

Default export

The default export is special:

// foo.ts
export default function factoryFunction() {
}

spion

#!/bin/bash

#----------------------------------------------------------------------------------
# Settings
#----------------------------------------------------------------------------------

#BANDN="Toggle,Freq,Band,Gain"
BAND1="1,150,1.3,-7"
BAND2="1,100,0.4,4"
BAND3="1,5400,0.9,-5"

spion

// A typesafe shopping cart in typescript.

// Immutable map :)

declare class Map<T, U> {
	set(t:T, u:U):Map<T, U>
	has(t:T):boolean;
	delete(t:T):Map<T,U>
	count:number;
}

spion

declare module "simple-router" {
    function mkRouter():SimpleRouter

    import express = require('express');

    interface Obj {}

    module mkRouter {
        export interface Request extends express.Request {

spion

let pending = new Promise((r,rj) => {})
let waitForever = () => pending
let reject = Promise.reject.bind(promise)
let identity = x => x
let promiseTransform = fns => p => p.then(fns.fullfilment, fns.rejection)

function any(promises) {
  let fulfillments = promises.map(promiseTransform({fullfilment: identity, rejection: waitForever}))
  let rejections   = promises.map(promiseTransform({fullfilment: waitForever, rejection: identity}))
  let firstFulfill = Promise.race(fulfillments);

spion

#!/bin/bash

# Usage: ./timeout-alert.sh <time> "alert commands to execute" "main command to execute"

(sleep $1 && eval $2 ) &
ALERTPID=$!
eval $3
kill $ALERTPID > /dev/null 2>&1

spion

#!/bin/bash

# Usage: ./timeout-alert.sh <time> "alert commands to execute" "main command to execute"

(sleep $1 && eval $2 ) &
ALERTPID=$!
eval $3
kill $ALERTPID > /dev/null 2>&1