Rick Waldron rwaldron

Learn JavaScript concepts with the Chrome DevTools

Authored by Peter Rybin , Chrome DevTools team

In this short guide we'll review some new Chrome DevTools features for "function scope" and "internal properties" by exploring some base JavaScript language concepts.

Closures

Let's start with closures – one of the most famous things in JS. A closure is a function, that uses variables from outside. See an example:

It All Starts With Templates

An Ember application starts with its main template. Put your header, footer, and any other decorative content in application.handlebars.

<header>
  <img src="masthead">
</header>

<footer>

These instructions work for the Raspberry Pi running Raspbian (hard float) and create a hardware optimized version of NodeJS for the Raspberry PI, (and include a working install and NPM!!!):

Install Raspbian - http://www.raspberrypi.org/downloads
Install the necessary dependecies:

sudo apt-get install git-core build-essential

(If you just installed git then you need to administer your git identity first, else adding the patches below will fail!!!)

	cipreq() {

	if [ -z "$1" ]
	then
	echo `git log -1 --no-merges --pretty=format:'git commit -a --author="'"%an <%aE>"'" --message="'"%s %b"'"'`
	return 1
	fi

	AUTHOR=$1

	var serialport = require('node-serialport')

	var sp = new serialport.SerialPort("/dev/ttyO3", {
	parser: serialport.parsers.raw,
	baud: 9600
	})

	sp.on('data', function(chunk) {
	console.log(chunk.toString('hex'), chunk.toString(), chunk)
	})

	/* Controlling cheap USB LED notifiers with node-hid */

	var Notifier = function(hid) {
	this.hid = hid;
	this.colors = ['OFF', 'BLUE', 'RED', 'GREEN', 'CYAN', 'PURPLE', 'YELLOW', 'WHITE'];
	};
	Notifier.prototype.write = function(arBytes) {
	this.hid.write(arBytes);
	};
	Notifier.prototype.color = function(value) {

	// ---------------------------------------------------------------------
	// 1. UNCONTROVERSIAL AMONGST TC39
	// ---------------------------------------------------------------------

	// read before write throws
	{
	console.log(x); // throws
	let x = 12;
	console.log(x);
	}

	" 11 11 ",
	"1 11 1",
	"1 1",
	"1 1",
	" 1 1 ",
	" 1 1 ",
	" 11 ",
	" "

	vs

	for (var i = 0; i < 1024 * 1024; i++) {
	process.nextTick(function () { Math.sqrt(i) } )
	}