djspiewak

Quick Tips for Fast Code on the JVM

I was talking to a coworker recently about general techniques that almost always form the core of any effort to write very fast, down-to-the-metal hot path code on the JVM, and they pointed out that there really isn't a particularly good place to go for this information. It occurred to me that, really, I had more or less picked up all of it by word of mouth and experience, and there just aren't any good reference sources on the topic. So… here's my word of mouth.

This is by no means a comprehensive gist. It's also important to understand that the techniques that I outline in here are not 100% absolute either. Performance on the JVM is an incredibly complicated subject, and while there are rules that almost always hold true, the "almost" remains very salient. Also, for many or even most applications, there will be other techniques that I'm not mentioning which will have a greater impact. JMH, Java Flight Recorder, and a good profiler are your very best friend! Mea

fdidron

//Usage
import React from 'react';
import { BrowserRouter as Router } from 'react-router-dom';
import Route from './AuthRoute';

import Login from './Login';
import Private from './Private';

export default () => 
  <Router>

kwilczynski

SHELL := /bin/bash

REV := $(shell git rev-parse HEAD)
CHANGES := $(shell test -n "$$(git status --porcelain)" && echo '+CHANGES' || true)

TARGET := packer-provisioner-itamae-local
VERSION := $(shell cat VERSION)

OS := darwin freebsd linux openbsd
ARCH := 386 amd64

Hilaryous

Vim Cheat Sheet

Cursor Movement

  h        - move cursor left
  j        - move cursor down
  k        - move cursor up
  l        - move cursor right
  w        - jump forwards to the start of a word

W - jump forwards to the start of a word (words can contain punctuation)

mjohnsullivan

// Parsing arbitrary JSON using interfaces in Go
// Demonstrates how to parse JSON with abritrary key names
// See https://blog.golang.org/json-and-go for more info on generic JSON parsing

package main

import (
	"encoding/json"
	"fmt"
)

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

bstancil

-- These queries let you define find user sessions against event data
-- logged to Segment SQL, Snowplow, or Google BigQuery.
-- For more details, see the full post:
-- LINK


--- SEGMENT SQL
-- Finding the start of every session
SELECT *
  FROM (

StephanHoyer

Icons have been part of applications since ages. Also most websites rely on icons. There were several ways to use them. First we used plain files then image sprites to reduce requests. Nowadays everyone uses icon fonts like font-awesome or glyphicons.

They are infinetly scaleable and styleable with css. The downside is they use pseudo elements for displaying. This is not only difficult to handle but also non-optimal for accessibilty.

A famous CSS-Tricks post brings SVG icons into play. The are also scalable and they behave like normal images. But we also want to have a sprite to not load any images seperatly and kill our servers and our sites performance. The proposed version is to create sprites with grunt or gulp using the symbol-trick. It's basically add every icon to a hidden sprite-image and give every icon an id-property.

<svg xmlns="http://www.w3.org/2000/svg" style="display: none;">
  
  <symbol id="beaker" viewBox="214.7 0 182.6 792">

totty90

define(function(require, exports, module){
    var React     = require('react');
    var constants = require('constants');
    var _         = require('underscore');
    var motivationalLines = [
        'Life isn’t about getting and having, it’s about giving and being.',
        'Whatever the mind of man can conceive and believe, it can achieve.',
        'You miss 100% of the shots you don’t take.',
        'Every strike brings me closer to the next home run.',
        'The mind is everything. What you think you become.',

tbeseda

Visualize data from a SmartThings sensor with Dweet and Freeboard

My SmartThings multisensor is a great little piece of technology. It reports, in real time, motion, temperature, and open/close state of my back door. The iOS app is slick, too, but I wanted a way to view it from my computer and have access to historical data.
Enter Dweet and Freeboard from Buglabs.

The SmartThings SmartApp and Dweet

There's actually no setup required on Dweet (but be sure to check out their nifty demo). It just starts eating data and making it available for use via HTTP/JSON!