Cham : Springer, c2019.

The Kindle Paperwhite is my go-to device for reading as I simply love the display. In contrast to my tablet or phone, I can use the device outdoors in direct sun-light without any issues which is a huge plus.

complete article

Hayden Library - PN1995.9.L28 B97 2018

Hayden Library - PN1995.9.P7 L33 2019

Online Resource

Connecting with God in difficult seasons.

We talk to 50 Cent about his latest line of headphones, the wireless SMS Syncs.  These cans feature a built-in EQ and utilize Kleer technology for wireless audio.

Willmott, Phil (Phil R.), author

Using a de-facto standard like CommonJS is for modules, I've implemented a Promise based import after TC39 proposal, which also accepts promises based module.exports.

Backward compatible and deadly simple, this proposal needs some adoption in order to push it further at TC39 or NodeJS.

Don't miss the post!

Online Resource

Hayden Library - P204.T96 2018

Online Resource

Online Resource

Marginson, Simon

Online Resource

The synchronisation coincided with Prime Minister Manmohan Singh's three-day visit to Russia.

The panelists discuss asynchronous programming.

Pete Hodgson crosses over from the iPhreaks podcasts to talk with the Jabber gang about testing asynchronous Javascript with promises.

The panelists talk to Elliot Kember about asynchronous UI and non-blocking interactions.

Panel:

• Charles Max Wood
• AJ O’Neal
• Aimee Knight

Special Guests: Valeri Karpov 

In this episode, the panel talks with programmer, Valerie Karpov from Miami, Florida. He is quite knowledgeable with many different programs, but today’s episode they talk specifically about Async/Await and Promise Generators. Val is constantly busy through his different endeavors and recently finished his e-book, “Mastering Async/Await.” Check-out Val’s social media profiles through LinkedIn, GitHub, Twitter, and more.

Show Topics:

1:20 – Val has been on previous episodes back in 2013 & 2016.

1:37 – Val’s background. He is very involved with multiple companies. Go checkout his new book!

2:39 – Promises generators. Understand Promises and how things sync with Promises. Val suggests that listeners have an integrated understanding of issues like error handling.

3:57 – Chuck asks a question.

6:25 – Aimee’s asks a question: “Can you speak to why someone would want to use Async/Await?”

8:53 – AJ makes comments.

10:09 – “What makes an Async/Await not functional?” – Val

10:59 – “What’s wrong with Promises or Async/Await that people don’t like it?” - AJ

11:25 – Val states that he doesn’t think there really is anything wrong with these programs it just depends on what you need it for. He thinks that having both gives the user great power.

12:21 – AJ’s background is with Node and the Python among other programs.

12:55 – Implementing Complex Business Logic.

15:50 – Val discusses his new e-book.

17:08 – Question from Aimee.

17:16 – AJ answers question. Promises should have been primitive when it was designed or somewhat event handling.

17:46 – The panel agrees that anything is better than Call Backs.

18:18 – Aimee makes comments about Async/Await.

20:08 – “What are the core principles of your new e-book?” – Chuck

20:17 – There are 4 chapters and Val discusses, in detail, what’s in each chapter.

22:40 – There could be some confusion from JavaScript for someone where this is their first language. Does Async/Await have any affect on the way you program or does anything make it less or more confusing in the background changes?

24:30 – Val answers the before-mentioned question. Async/Await does not have anyway to help with this (data changes in the background).

25:36 – “My procedural code, I know that things won’t change on me because it is procedural code. Is it hard to adjust to that?” – AJ

26:01 – Val answers the question.

26:32 – Building a webserver with Python. 

27:31 – Aimee asks a question: “Do you think that there are cases in code base, where I would want to use Promises? Not from a user’s perspective, but what our preferences are, but actual performance. Is there a reason why I would want to use both or be consistent across the board?”

28:17 – Val asks for some clarification to Aimee’s question.

29:14 – Aimee: “My own personal preference is consistency. Would I want to use Promises in ‘x’ scenario and/or use Async/Await in another situation?”

32:28 – Val and AJ are discussing and problem solving different situations that these programs

33:05 – “When would you not want to use Async/Await?” – AJ

33:25 – Val goes through the different situations when he would not use Async/Await. 

33:44 – Chuck is curious about other features of Async/Await and asks Val.

36:40 – Facebook’s Regenerator

37:11 – AJ: “Back in the day, people would be really concerned with JavaScript’s performance even with Chrome.” He continues his thoughts on this topic.

38:11 – Val answers the AJ’s question.

39:10 – Duck JS probably won’t include generators.

41:18 – Val: “Have anyone used Engine Script before?” The rest of the panel had never heard of this before.

42:09 – Windows Scripting Host

42:56 – Val used Rhino in the past.

43:40 – Val: “Going back to the web performance question...”

47:08 – “Where do you see using Async/Await the most?” – Chuck

47:55 – Val uses Async/Await for everything on the backend because it has made everything so easy for him.

48:23 – “So this is why you really haven’t used Web Pack?” – AJ

49:20 – Let’s go to Aimee’s Picks!

50:18 – AJ’s story, first, before we get to Promises.

54:44 – Let’s transition to Promises Finally.

54:53 – Val talks about Promises Finally.

59:20 – Picks

Links:

• JavaScript
• Valeri Karpov’s GitHub
• Valeri Karpov’s Twitter
• Valeri Karpov’s LinkedIn
• New E-Book: Mastering Async/Await
• Node
• Python
• Windows Scripting Host
• Facebook’s Regenerator
• Rhino

Sponsors:

• Kendo UI
• Sentry
• Digital Ocean
•  

Picks:

Charles

• YouTube Video “IKEA” by Coulton
• Conference
• Amazon Prime Day

Aimee

• Blog Post Article

AJ

• IKEA
• https://ppl.family

Val

• https://www.npmjs.com/package/serve
• http://bit.ly/ultimate-skiing
• http://asyncawait.net/jsjabber
• New E-Book: Mastering Async/Await

Valeri Karpov is a maintainer on Mongoose, has started a few companies, and works for a company called Booster Fuels. Today’s topic debugging with Async/Await. The panel talks about some of the challenges of debugging with Async. AJ, however, has never encountered the same problems, so he shares his debugging method. 

Valeri differentiates between .catch vs try...catch, and talks about why he prefers .catch. There are two ways to handle all errors in an async function without leading to an unhandled promise rejection. The first is to wrap the entire body of the async function in a try...catch, has some limitations. Calling an async function always returns a promise, so the other approach is calling .catch on the promise to handle any errors that occur in that function body. One of the key differences is if you return a promise within an async function, and that return promise is wrapped in a try...catch, the catch block won’t get called if that promise is rejected, whereas if you call .catch on the promise that the function returns, you’ll actually catch that error. There are rare instances where this can get tricky and unintuitive, such as where you have to call new promise and have resolve and reject, and you can get unexpected behavior.

The panel discusses Valeri’s current favorite JS interview question, which is,  “Given a stream, implement a function called ‘stream to promise’ that, given a stream, returns a promise that resolves to the concatenation of all the data chunks emitted by the stream, or rejects if the stream emits an error event.” It’s really simple to get this qustion right, and really simple to get it wrong, and the difference can be catastrophic. AJ cautions listeners to never use the data event except in the cases Val was talking about, only use the readable event.

The conversation turns to the function of a readable event. Since data always pushes data, when you get a readable event, it’s up to you to call read inside the function handler, and then you get back a chunk of data, call read again and again until the read returns null. When you use readable, you are in control and you avoid piling functions into RAM. In addition, the right function will return true or false to let you know if the buffer is full or not. This is a way to mix imperative style into a stream.

The next discussion topics are the differences between imperative style and reactive style and how a waits and promises work in a normal four loop. A wait suspends the execution of a function until the promise is resolved. Does a wait actually stop the loop or is it just transpiling like a promise and it doesn’t stop the loop. AJ wrote a module called Batch Async to be not as greedy as promise.all but not as limited as other options.

The JavaScript panelists talk about different async iterators they’ve used, such as Babel. They discuss the merits of Babel, especially since baseline Android phones (which a significant portion of the population of the world uses) run UC Browser that doesn’t support Babel, and so a significant chunk of the population of the world. On the other hand, if you want to target a large audience, you need to use Babel.

Since frameworks in general don’t handle async very well, the panel discusses ways to mitigate this. They talk about different frameworks like Vue, React, and Express and how they support async functions. They discuss why there is no way for you to actually cancel an async option in an actual case, how complex canceling is, and what you are really trying to solve for in the cancellation process. 

Canceling something is a complex problem. Valeri talks about his one case where he had a specific bug that required non-generic engineering to solve, and cancelling actually solved something. When AJ has come across cancellation issues, it’s very specific to that use case. The rest of the panelists talk about their experiences with having to cancel something. 

Finally, they talk about their experience with async generator functions. A generator is a function that lets you enter into the function later. This makes sense for very large or long running data sets, but when you have a bounded items, don’t complicate your code this way. When an async generator function yields, you explicitly need to call next in order for it to pick up again. If you don’t call ‘next’, it’s essentially cancelled. Remember that object.keys and object.values are your friends. 

Panelists

• Christopher Buecheler

• AJ O’Neal

• Charles Max Wood

With special guest: Valeri Karpov

Sponsors

• The DevEd Podcast

• Sentry use the code “devchat” for 2 months free on Sentry’s small plan

• Adventures in DevOps

Links

• Mongoose

• Express 5

• Node Streams

• Pull Streams

• Masteringjs.io

• MongoDB

• Babel

• HTML

• Webpack

• Vue

• Express

• RxJS

• Console.log

• Json.stringify

• Batchasync.js

• How to Write Batch Async Functions

Follow DevChatTV on Facebook and Twitter

Picks

AJ O’Neal:

• Ethan Garofolo YouTube

Christopher Buecheler:

• Functional Design Patterns for Express.js

Charles Max Wood:

• Microsoft Ignite

• Maxcoders.io

Valeri Karpov:

• Follow Valeri on Twitter @code_barbarian and Github @vkarpov15

• Masteringjs.io

• Jurassic Park: A Novel

A 58-year-old woman presents with no relevant medical history with syncope, elevated troponin and D-dimer levels, and multiple large bilateral pulmonary emboli. What would you do next?

I’ve started using a backup strategy based on that originally described by Jamie Zawinski and subsequently covered in Jeff Atwood’s What’s your backup strategy? article. It works by incrementally backing up your data to a bootable clone of your computer’s internal drive, in order to replace the internal drive when it fails.

This script is maintained in my dotfiles repo. Please report problems or improvements in the issue tracker.

This post is mainly to document – for myself as much as anything – the process I went through in order to implement an incremental backup strategy in OS X 10.6+. Use at your own risk. Feel free to suggest improvements if you know of any.

Formatting and partitioning the drive

With your backup drive in its enclosure, connect the drive to your Mac and open the Disk Utility application.

1. Click on the disk’s name. This should bring up a “Partition” tab in the right panel.
2. Click on the “Partition” tab.
3. Under “Volume scheme” select the number of partitions you need. Probably “1 partition” if it is to match your internal disk.
4. Under “Name” enter the volume name you want to use, e.g., “Backup”.
5. Under “Format” select “Mac OS X Extended (Journaled)”, which is necessary if the disk is to be bootable.
6. Click “Options” and check that “GUID Partition Table” is selected.
7. Click “Apply”.

This will format and partition the disk. The partition(s) should now show up in the Finder and on the Desktop.

Enable ownership permissions

The new partition needs permissions to be enabled to avoid chown errors when using rsync. To do this, select the partition and view its information page (using “Get Info” or Command+I). Expand the “Ownership & Permissions” section and uncheck “Ignore ownership on this volume”

Backup script

The backup script uses rsync – a fast and versatile file copying tool – to manage the copying and moving of data between volumes. You need to install rsync 3 (this is easily done using Homebrew: brew install https://raw.github.com/Homebrew/homebrew-dupes/master/rsync.rb). Rsync offers a wide variety of options and only copies the differences between the source files and the existing files in the destination, making it ideal for incremental backups. You can find out more about rsync in the rsync documentation

The following is the contents of a script I’ve named backup. I’m using it to backup all of the data on my internal disk, with a specified set of exceptions contained within a file called .backupignore.

#!/bin/bash

# Disc backup script
# Requires rsync 3

# Ask for the administrator password upfront
sudo -v

# IMPORTANT: Make sure you update the `DST` variable to match the name of the
# destination backup drive

DST="/Volumes/Macintosh HD/"
SRC="/"
EXCLUDE="$HOME/.backupignore"

PROG=$0

# --acls                   update the destination ACLs to be the same as the source ACLs
# --archive                turn on archive mode (recursive copy + retain attributes)
# --delete                 delete any files that have been deleted locally
# --delete-excluded        delete any files (on DST) that are part of the list of excluded files
# --exclude-from           reference a list of files to exclude
# --hard-links             preserve hard-links
# --one-file-system        don't cross device boundaries (ignore mounted volumes)
# --sparse                 handle sparse files efficiently
# --verbose                increase verbosity
# --xattrs                 update the remote extended attributes to be the same as the local ones

if [ ! -r "$SRC" ]; then
    logger -t $PROG "Source $SRC not readable - Cannot start the sync process"
    exit;
fi

if [ ! -w "$DST" ]; then
    logger -t $PROG "Destination $DST not writeable - Cannot start the sync process"
    exit;
fi

logger -t $PROG "Start rsync"

sudo rsync --acls 
           --archive 
           --delete 
           --delete-excluded 
           --exclude-from=$EXCLUDE 
           --hard-links 
           --one-file-system 
           --sparse 
           --verbose 
           --xattrs 
           "$SRC" "$DST"

logger -t $PROG "End rsync"

# Make the backup bootable
sudo bless -folder "$DST"/System/Library/CoreServices

exit 0

Adapted from the rsync script at Automated OSX backups with launchd and rsync

This is the contents of the .backupignore file.

.Spotlight-*/
.Trashes
/afs/*
/automount/*
/cores/*
/dev/*
/Network/*
/private/tmp/*
/private/var/run/*
/private/var/spool/postfix/*
/private/var/vm/*
/Previous Systems.localized
/tmp/*
/Volumes/*
*/.Trash

Adapted from the excludes file at Automated OSX backups with launchd and rsync

Every time the script runs, messages will be written to the system log.

Check that the source (SRC) and destination (DST) paths in the script are correct and match the volume name that you chose when partitioning the disk. Wrapping the $SRC and $DST variables in double quotes ensures that the script will work even if your volume names contain spaces (e.g. “Macintosh Backup”).

The command option --exclude-from tells the script where to find the file containing the exclude patterns. Make sure you either have .backupignore in the home directory or that you update this part of the command to reference the full path of the excludes file.

Running the backup script

You can run the script from the command line, or make it executable from the Finder or the Desktop:

1. Type the following into the command line to ensure that you have permission to execute the script:

   chmod +x /path/to/rsync_backup.sh
   

2. Remove the .sh extension from the script.

3. Create an alias of the script and move it to the Desktop.
4. Double click the icon to run the backup script.

It’s important to run the script regularly in order to keep the backup in sync with your internal disk. If you have a desktop computer, or you never turn off your laptop, you can automate the running of the script by setting up a cron job.

Checking the disk is bootable

Once you’ve run the backup script, you should test that the backup disk is bootable. To do this, restart your computer and hold down the Alt/Option key. Your backup disk should be presented, with the volume name you chose, as a bootable disk.

When I first booted my backup, the terminal displayed the following line:

dyld: shared cached file was build against a different libSystem.dylib, ignoring cache

According to this article, the fix for this is to update the cache by entering the following into the terminal:

sudo update_dyld_shared_cache -force

That should be everything you need to start implementing an incremental backup strategy when using OS X.

I was supposed to be in Plymouth yesterday, giving the opening talk at this year’s Future Sync conference. Obviously, that train journey never happened, but the conference did.

The organisers gave us speakers the option of pre-recording our talks, which I jumped on. It meant that I wouldn’t be reliant on a good internet connection at the crucial moment. It also meant that I was available to provide additional context—mostly in the form of a deluge of hyperlinks—in the chat window that accompanied the livestream.

The whole thing went very smoothly indeed. Here’s the video of my talk. It was The Layers Of The Web, which I’ve only given once before, at Beyond Tellerrand Berlin last November (in the Before Times).

As well as answering questions in the chat room, people were also asking questions in Sli.do. But rather than answering those questions there, I was supposed to respond in a social medium of my choosing. I chose my own website, with copies syndicated to Twitter.

Here are those questions and answers…

The first few questions were about last years’s CERN project, which opens the talk:

Based on what you now know from the CERN 2019 WorldWideWeb Rebuild project—what would you have done differently if you had been part of the original 1989 Team?

I responded:

Actually, I think the original WWW project got things mostly right. If anything, I’d correct what came later: cookies and JavaScript—those two technologies (which didn’t exist on the web originally) are the source of tracking & surveillance.

The one thing I wish had been done differently is I wish that JavaScript were a same-origin technology from day one:

https://adactio.com/journal/16099

Next question:

How excited were you when you initially got the call for such an amazing project?

My predictable response:

It was an unbelievable privilege! I was so excited the whole time—I still can hardly believe it really happened!

https://adactio.com/journal/14803

https://adactio.com/journal/14821

Later in the presentation, I talked about service workers and progressive web apps. I got a technical question about that:

Is there a limit to the amount of local storage a PWA can use?

I answered:

Great question! Yes, there are limits, but we’re generally talking megabytes here. It varies from browser to browser and depends on the available space on the device.

But files stored using the Cache API are less likely to be deleted than files stored in the browser cache.

More worrying is the announcement from Apple to only store files for a week of browser use:

https://adactio.com/journal/16619

Finally, there was a question about the over-arching theme of the talk…

Great talk, Jeremy. Do you encounter push-back when using the term “Progressive Enhancement”?

My response:

Yes! …And that’s why I never once used the phrase “progressive enhancement” in my talk. ????

There’s a lot of misunderstanding of the term. Rather than correct it, I now avoid it:

https://adactio.com/journal/9195

Instead of using the phrase “progressive enhancement”, I now talk about the benefits and effects of the technique: resilience, universality, etc.

'The night, I have to sadly admit, was a let-down and Mr Bieber, you kind of broke my heart,' says a Belieber.

Online Resource