Soichi Takamura piglovesyou

WTF Flow

[Flow][] static type checker is a wonderful attempt to bring [algebric data types][] to JS. It is still fairly new project and there for has few WTFs that can pull you down the rabbit hole. This document is attempt to document things that may seem like a WTF from the perspective of JS developer who tries to employ static type checker, or in other words, some items on the list may be very subjective & based on the background of the writer.

Polymorphic type that is a function

It is very likely that one will wind up using [Polymorphic functions][] to solve a more general problem. And if you define type alias for such a function you may be puzzled what is the right syntax should be used for such type definition.

Let's start with:

URLs into Indexed DB, via Service Workers

Let's say you're using Indexed DB for the offline data store for a catalog. One of the object stores contains product images. Wouldn't it be great if you could just have something like this in your catalog page?

<img src="indexeddb/database/store/id">

About

When using ArchLinux, I typically prefer to use an AUR helper like pacaur or yaourt to automate away the process of installing a community package.

Ansible's pacman module is great, but it doesn't support AUR packages or pacman's -U flag. Installing AUR packages with Ansible seemed to be left as an exercise to the user, and since AUR helpers do not come with a fresh Arch install, I

Deprecating `transferPropsTo`

It's a common pattern in React to wrap a component in an abstraction. The outer component exposes a simple property to do something that might have more complex implementation details.

We used to have a helper function called transferPropsTo. We no longer support this method. Instead you're expected to use a generic object helper to merge props.

render() {
 return Component(Object.assign({}, this.props, { more: 'values' }));

Installing Cassandra on Mac OS X

Install Homebrew

Homebrew is a great little package manager for OS X. If you haven't already, installing it is pretty easy:

ruby -e "$(curl -fsSL https://raw.github.com/Homebrew/homebrew/go/install)"

vimで使うキーの機能使用頻度と打ちやすさの整理

vimで使うキーの機能使用頻度と打ちやすさを整理してみました。今回整理したのはnormalモードについてだけです。機能の使用頻度と打ちやすさは、完全に個人の見解です。キーボードによっても打ちやすさは変わると思います。

すべてのキーを網羅しているわけではありません。

	var Rx = require('rx');
	var readline = require('readline');
	var fs = require('fs');

	var rl = readline.createInterface({
	input: fs.createReadStream('lines.txt')
	});

	var lines = Rx.Observable.fromEvent(rl, 'line')
	.takeUntil(Rx.Observable.fromEvent(rl, 'close'))

	'use strict';

	var KEYS = {
	enter: 13,
	left: 37,
	right: 39,
	escape: 27,
	backspace: 8,
	comma: 188,
	shift: 16,

	var webdriver = require('selenium-webdriver');
	var fs = require('fs');

	var driver = new webdriver.Builder().build();

	webdriver.WebDriver.prototype.saveScreenshot = function(filename) {
	return driver.takeScreenshot().then(function(data) {
	fs.writeFile(filename, data.replace(/^data:image\/png;base64,/,''), 'base64', function(err) {
	if(err) throw err;
	});

	[Default Applications]
	application/arj=xarchiver.desktop;
	application/deb=xarchiver.desktop;
	application/java-archive=openjdk-6-java.desktop;
	application/msexcel=libreoffice-calc.desktop;
	application/mspowerpoint=libreoffice-impress.desktop;
	application/msword=libreoffice-writer.desktop;
	application/ogg=vlc.desktop;
	application/pdf=epdfview.desktop;gimp.desktop;gimp.desktop;
	application/pkcs12=gcr-viewer.desktop;