danielgtaylor

Moving to ES6 from CoffeeScript

I fell in love with CoffeeScript a couple of years ago. Javascript has always seemed something of an interesting curiosity to me and I was happy to see the meteoric rise of Node.js, but coming from a background of Python I really preferred a cleaner syntax.

In any fast moving community it is inevitable that things will change, and so today we see a big shift toward ES6, the new version of Javascript. It incorporates a handful of the nicer features from CoffeeScript and is usable today through tools like Babel. Here are some of my thoughts and issues on moving away from CoffeeScript in favor of ES6.

While reading I suggest keeping open a tab to Babel's learning ES6 page. The examples there are great.

Punctuation

Holy punctuation, Batman! Say goodbye to your whitespace and hello to parenthesis, curly braces, and semicolons again. Even with the advanced ES6 syntax you'll find yourself writing a lot more punctuatio

cdipaolo

// haversin(θ) function
func hsin(theta float64) float64 {
	return math.Pow(math.Sin(theta/2), 2)
}

// Distance function returns the distance (in meters) between two points of
//     a given longitude and latitude relatively accurately (using a spherical
//     approximation of the Earth) through the Haversin Distance Formula for
//     great arc distance on a sphere with accuracy for small distances
//

josephspurrier

/*
fmt.Println(Bitmask(0x6).IsSet(0x2))
fmt.Println(Bitmask(f.FileHeader.Characteristics).ListDescriptions(charValues))
fmt.Println(Bitmask(f.FileHeader.Characteristics).ListValues(charValues))
*/

type Bitmask uint16

// BitValue is a value and a description
type BitValue struct {

justmoon

'use strict';

module.exports = function CustomError(message, extra) {
  Error.captureStackTrace(this, this.constructor);
  this.name = this.constructor.name;
  this.message = message;
  this.extra = extra;
};

require('util').inherits(module.exports, Error);

cdmckay

select decode(replace('45774962-e6f7-41f6-b940-72ef63fa1943'::text, '-', ''), 'hex');

-- And here's how to convert it to the ShortUUID format used in Process Street
select replace(encode(substring(decode(replace('45774962-e6f7-41f6-b940-72ef63fa1943'::text, '-', ''), 'hex') from 9 for 8) || 
substring(decode(replace('45774962-e6f7-41f6-b940-72ef63fa1943'::text, '-', ''), 'hex') from 1 for 8), 'base64'), '=', '');

aseemk

Pattern 1: Pre-fetch the result, and cache it.

The result will hopefully already be available when needed, and the async call will be made only once.

fooFuture = fetchFoo !_

# anytime when needed:
foo = fooFuture _ # supports multiple calls!

jashkenas

#!/usr/bin/env coffee

fs = require 'fs'
sh = require 'execSync'

config = JSON.parse fs.readFileSync 'package.json'

fs.renameSync 'package.json', 'package.json.real'

name = config.name = "#{config.name}-semver"

yocontra

Stealing WiFi

/etc/hosts

This will let you access any google owned site. This includes: youtube, google cache, google translate, google search, gmail, google news, etc.

• Install the HTTPS Everywhere extension
• Add these rules to your /etc/hosts file

coolaj86

Here's how you validate a mailgun webhook in Node.js (as per the mailgun docs for securing webhooks)

'use strict';

var scmp = require('scmp')
  , crypto = require('crypto')
  . mailgunPrivateKey = 'XXXXXXXXXXXXX'
  , mailgunTokens = {}
  , mailgunExpirey = 15 * 60 * 1000

moxious

A Neo4J Experiment: Lookup Nodes vs. Labels

Background

In previous versions of neo4j, people have used an "lookup node" pattern to access certain subgraphs or subsets of their data. The "lookup node" pattern basically creates a single node to act as the entry of an index, and relationships from that "lookup node" to whatever the contents of the index would be.

This can also be used for other use cases, such as creating partitions.

More broadly, these kinds of modeling tricks turn out to be very useful to capture a variety of different kinds of domain semantics, including all sorts of set membership expression:

• Expressing that all linked nodes share some common property, without expressing the property individually in every node (i.e. companies whose home country = 'USA')