Tao Wu metaphox

#System Design Cheatsheet

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

##Basic Steps

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?

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout. This is also called reflow or layout thrashing, and is common performance bottleneck.

Element

Box metrics

elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent
elem.clientLeft, elem.clientTop, elem.clientWidth, elem.clientHeight
elem.getClientRects(), elem.getBoundingClientRect()

Mensch font, Source Code Pro, Webkit, Chrome, Firefox, Kaleidoscope, iTerm, Sublime Text, Sequel Pro, Codekit,

To open a remote URL at application startup with phoneGap 2.0 :

after project creation, in XCode expand "CordovaLib.xcodeproj" and open "Classes/Cleaver/CDVViewController.m" then edit the code : replace

NSString* startFilePath = [self pathForResource:self.startPage];

by

NSString* startFilePath = self.startPage;

One-line Tree in Python

Using Python's built-in defaultdict we can easily define a tree data structure:

def tree(): return defaultdict(tree)

That's it!

	/* bling.js */

	window.$ = document.querySelectorAll.bind(document)

	Node.prototype.on = window.on = function (name, fn) {
	this.addEventListener(name, fn)
	}

	NodeList.prototype.__proto__ = Array.prototype

	import javafx.application.Application;
	import javafx.collections.*;
	import javafx.geometry.Pos;
	import javafx.scene.*;
	import javafx.scene.chart.*;
	import javafx.scene.chart.XYChart;
	import javafx.scene.control.*;
	import javafx.scene.layout.*;
	import javafx.scene.shape.Line;
	import javafx.stage.Stage;

	// http://paulirish.com/2011/requestanimationframe-for-smart-animating/
	// http://my.opera.com/emoller/blog/2011/12/20/requestanimationframe-for-smart-er-animating

	// requestAnimationFrame polyfill by Erik Möller. fixes from Paul Irish and Tino Zijdel

	// MIT license

	(function() {
	var lastTime = 0;
	var vendors = ['ms', 'moz', 'webkit', 'o'];

	var user = {
	validateCredentials: function (username, password) {
	return (
	(!(username += '') \|\| username === '') ? { error: "No Username Given.", field: 'name' }
	: (!(username += '') \|\| password === '') ? { error: "No Password Given.", field: 'pass' }
	: (username.length < 3) ? { error: "Username is less than 3 Characters.", field: 'name' }
	: (password.length < 4) ? { error: "Password is less than 4 Characters.", field: 'pass' }
	: (!/^([a-z0-9-_]+)$/i.test(username)) ? { error: "Username contains invalid characters.", field: 'name' }
	: false
	);

	# requires root permissions in /usr/bin/

	star = String.new
	8.times { star += "*" }
	Star = "\n#{star * 3}\n"

	def newblock string
	puts "\n#{Star}#{string}#{Star}\n"
	end