Dale Ryan lnfel

Stuff I wish I'd known sooner about service workers

I recently had several days of extremely frustrating experiences with service workers. Here are a few things I've since learned which would have made my life much easier but which isn't particularly obvious from most of the blog posts and videos I've seen.

I'll add to this list over time – suggested additions welcome in the comments or via twitter.com/rich_harris.

Use Canary for development instead of Chrome stable

~~Chrome 51 has some pretty wild behaviour related to console.log in service workers. Canary doesn't, and it has a load of really good service worker related stuff in devtools.~~

This is a working example on how to store CryptoKeys locally in your browser. We are able to save the objects, without serializing them. This means we can keep them not exportable (which might be more secure?? not sure what attack vectors this prevents).

To try out this example, first make sure you are in a browser that has support for async...await and indexedDB (latest chrome canary with chrome://flags "Enable Experimental Javascript" works). Load some page and copy and paste this code into the console. Then call encryptDataSaveKey(). This will create a private/public key pair and encrypted some random data with the private key. Then save both of them. Now reload the page, copy in the code, and run loadKeyDecryptData(). It will load the keys and encrypted data and decrypt it. You should see the same data logged both times.

Hyperlinks (a.k.a. HTML-like anchors) in terminal emulators

[ Update 2025-03-24: Commenting is disabled permanently. Previous comments are archived at web.archive.org. ]

Most of the terminal emulators auto-detect when a URL appears onscreen and allow to conveniently open them (e.g. via Ctrl+click or Cmd+click, or the right click menu).

It was, however, not possible until now for arbitrary text to point to URLs, just as on webpages.

	#!/bin/bash

	# Tom Hale, 2016. MIT Licence.
	# Print out 256 colours, with each number printed in its corresponding colour
	# See http://askubuntu.com/questions/821157/print-a-256-color-test-pattern-in-the-terminal/821163#821163

	set -eu # Fail on errors or undeclared variables

	printable_colours=256

	type FilterOperator = 'AND' \| 'OR';
	type FiltersBy<T> = {
	[K in keyof T]?: (value: T[K]) => boolean;
	};

	/**
	* Factory function that creates a specialized function to filter
	* arrays, by validating all filters (AND operator),
	* or validating just one of the filters (OR operator).
	* @param operator Method to validate all filters: AND, OR

	/*
	Template literals for-loop example
	Using `Array(5).join(0).split(0)`, we create an empty array
	with 5 items which we can iterate through using `.map()`
	*/

	var element = document.createElement('div')
	element.innerHTML = `
	<h1>This element is looping</h1>
	${Array(5).join(0).split(0).map((item, i) => `

	<?php

	namespace App\Providers;

	use Illuminate\Support\Collection;
	use Illuminate\Pagination\LengthAwarePaginator;

	class AppServiceProvider extends ServiceProvider
	{
	public function boot()

	/*
	Author: Jonathan Lurie - http://me.jonathanlurie.fr
	License: MIT

	The point of this little gist is to fix the issue of losing
	typed arrays when calling the default JSON serilization.
	The default mode has for effect to convert typed arrays into
	object like that: {0: 0.1, 1: 0.2, 2: 0.3} what used to be
	Float32Array([0.1, 0.2, 0.3]) and once it takes the shape of an
	object, there is no way to get it back in an automated way!

	<?php
	namespace App;

	use Illuminate\Pagination\LengthAwarePaginator;
	use App\Http\Controllers\Controller;


	class EloquentUser extends Controller {
	// these will work for eloquent, but not with a scout->search since scout is not building a query.
	public function paginate($query)

	<?php
	namespace Tests;
	use Mail;
	use Swift_Message;
	use Swift_Events_EventListener;

	trait MailTracking
	{
	/**
	* Delivered emails.