rantav

A few show tricks to find slow queries in mongodb

Enable profiling

First, you have to enable profiling

> db.setProfilingLevel(1)

Now let it run for a while. It collects the slow queries ( > 100ms) into a capped collections, so queries go in and if it's full, old queries go out, so don't be surprised that it's a moving target...

robmiller

#
# Working with branches
#

# Get the current branch name (not so useful in itself, but used in
# other aliases)
branch-name = "!git rev-parse --abbrev-ref HEAD"
# Push the current branch to the remote "origin", and set it to track
# the upstream branch
publish = "!git push -u origin $(git branch-name)"

staltz

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

---

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

---

raine

Read heroku logs output w/ bunyan

The stuff before the JSON in heroku logs output has to be cut off for bunyan to work.

$ heroku logs | sed -l 's/.*app\[web\..*\]\: //' | bunyan

Flag -l makes the output buffered by line.

yoavniran

The Ultimate Unit Testing Cheat-sheet

---

• Sinon Chai
• Chai
• Sinon

nolanlawson

// Promise.all is good for executing many promises at once
Promise.all([
  promise1,
  promise2
]);

// Promise.resolve is good for wrapping synchronous code
Promise.resolve().then(function () {
  if (somethingIsNotRight()) {
    throw new Error("I will be rejected asynchronously!");

MichalZalecki

/* VT100 terminal reset (<ESC>c) */

console.log('\033c');

/* numbers comparations */

> '2' == 2
true

> '2' === 2

joepie91

Promises reading list

This is a list of examples and articles, in roughly the order you should follow them, to show and explain how promises work and why you should use them. I'll probably add more things to this list over time.

This list primarily focuses on Bluebird, but the basic functionality should also work in ES6 Promises, and some examples are included on how to replicate Bluebird functionality with ES6 promises. You should still use Bluebird where possible, though - they are faster, less error-prone, and have more utilities.

I'm available for tutoring and code review :)

You may reuse all gists for any purpose under the WTFPL / CC0 (whichever you prefer).

vasanthk

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

1. Clarify and agree on the scope of the system

• User cases (description of sequences of events that, taken together, lead to a system doing something useful)
  • Who is going to use it?
  • How are they going to use it?

slavafomin

Here's how you could create custom error classes in Node.js using latest ES6 / ES2015 syntax.

I've tried to make it as lean and unobtrusive as possible.

Defining our own base class for errors

errors/AppError.js