Showing posts with label javascript. Show all posts
Showing posts with label javascript. Show all posts

This Week I Learned 2018 - Week 43

Last week post or something else from the archive instead.

What should you do when you're taking vacant possession of the new property in MY? Download (PDF) the document CIS 7:2014 QLASSIC (Quality Assessment System in Construction) from CIDB (Construction Industry Development Board Malaysia). Read it, print our the checklist, and go through your property to check for any defects. A homeowner have the legal rights to request property developer to rectify any issues within the Defect Liability Period (DLP). Is there any property developer who dares to include this checklist and document during the handover of a new property? Doubt so.

What is like to be a engineering manager? You have no power, take the heat for your team, and mostly focus on management (office politics).

Can you explain JavaScript's closure like I'm five? So many explanations but this example is simple enough to understand. The next step is to understand how closure was used in JS world. Current stage is like you know how to hit a pool ball but don't know why you need to hit it in a certain way.

What the heck is Perl11? (via HN) Well, is Perl 5 + Perl 6. Again, endless drama on the direction of the language itself. Perl have the opportunity to shine and lead the way but lost it. Perl 6, on the other hand, is too little too late.

What are $_, @_, %_ used for? I was quite surprised by the reply, but this answer was outstanding. The `$_` known as default topic variable can be referred as "fill in the blank". How come I never think of that analogy?

What are the non-free installed in your GNU/Linux distribution? Well, you can ask virtual RMS. Running this in my lappy shows the usual suspect packages. Yes, the proprietary drivers or firmwares still remains an unsolved problem for FOSS ecosystem that does not follow the Free System Distribution Guidelines (GNU FSDG).
$ vrms
                Non-free packages installed on x230

amd64-microcode                     Processor microcode firmware for AMD CPUs
fonts-ubuntu                        sans-serif font set from Ubuntu
i965-va-driver                      VAAPI driver for Intel G45 & HD Graphics family
intel-microcode                     Processor microcode firmware for Intel CPUs

                Contrib packages installed on x230

iucode-tool                         Intel processor microcode tool
ttf-mscorefonts-installer           Installer for Microsoft TrueType core fonts
virtualbox-5.2                      Oracle VM VirtualBox

  4 non-free packages, 0.2% of 2788 installed packages.
  3 contrib packages, 0.1% of 2788 installed packages.



This Week I Learned 2018 - Week 42

Last week post or some random stuff from the past.

Can you still be a developer in your 60s? Yes, it's still possible (look at Carl Sassenrath) but looking at the poster qualifications, he is over qualified and can be very intimidating to someone. The root cause is still "cultural fit' and ageism. Perhaps the poster can join the FOSS movement and contribute to it instead? Looking at the positive side, if you can survive until 60s and is fit to work, consider yourself very lucky than most people around that age. Nonetheless, just live below your means, be healthy, and enjoy what you're doing.

Why good sleep is crucial for learning? (via HN) More importantly, insufficient sleep can lead to numerous health issues and diminish your enjoyment of life. While you can't feel the impact when you're young, only at certain age, you will sense something have messed up somehow somewhere in your body. While it varies by person, but you needs at least 8.5 hours of sleep. If you're working, minus your working hours and travel times, with 8 hours of sleep, you're left with 6 hours to do your own errands. What can we do? Lifestyle changes and stick to a constant schedule, every day, every single damn day.

Is semicolon necessary in TypeScript? No but it's good to have it for consistent results, especially for new comer and coding convention. Even this is recommended by Ecma TC39. Off course with much debates and interesting point of view. I believe in the camp of better safe than sorry, just use semicolon;

What should a front end developer knows? Here are some common topics you will encounter eventually.
  1. ForEach vs. Map
  2. Promises vs. Generators
  3. What are the states in Promises?
  4. How many ways to lazy loading an image?
  5. What are the differences between Local Storage, Session Storage, and Cookies?
  6. What is event delegation in JavaScript?
  7. What is Cross-Origin Resource Sharing (CORS)?
What is 30 seconds of code? A bunch of JavaScript code snippets that demonstrates different features of this programming language.

Why we need `EXPORT` and `EXPORT_OK` in Perl? Well, we use the later if we need to let the library consumer or caller to explicitly import the module's symbols like subroutines, variables, constants, and so forth.

This Week I Learned 2018 - Week 39

Last week post or some old stuff.

《没换气过》。哭笑不得。音响还没弄好,期待播放这首歌试试看。

What is the worst pain you've ever experienced? For a woman, giving child labour. For a human, kidney stones. Contrary to the headline, (via HN), it's NOT beautiful at all but excruciating painful and can put a tough guy down to his knee.  Imagine coral reef passing your kidney or being stabbed in your kidney. If you're facing financial issue, maybe you should try roller coaster to get those stones out. Yes, it works and it's proven scientifically. What can you do right now? Prevention is still better than cure. Less salty food and drink plenty of water, like 2 litres per day.

How many books you should read at a time? Three. One hard, one easy, and one very easy. Currently I'm reading just one hard book (the material is so dry). The next step is to find another easy (fiction perhaps?) and very easy (manga?) book. Which time slot I should allocate to? Judging from my almost daily progress, is it possible to finish three books per month?

What is the most additive game in this year's JS13kGames competition? (via HN1024 Moves and I'm quite surprised and addicted to the games. The creativity shown in some of the submissions have reminded me how computing power have changed since the early days of computing.

How do we prevent muscle loss as we age? (via HN) Nothing but strength training. Every single fscking day. The MRI image below tells a lot about the importance of exercise towards maintaining your muscle flexibility regardless your age. The usual exercise regime should be 150 minutes and 3 times per week. Instead of cardio, maybe I should focus on strength training (weight lifting). Furthermore, building muscle actually burns more fat.


So Good They Can't Ignore You? (via HN) I can relate to the opposite view instead what of the book preaches. Is the book worth it? Yes, it's a popular-science writing made easy for layman. Once you've done with the book, you should explore something deeper like Flow: The Psychology of Optimal Experience. Read both book and the scientific papers published. Regardless your passions or skill sets, reality have to step in.

What is the dark side of working at a successful startup? Not surprisingly, money and lots of money. Money changed people. Sadly, towards the evil side of human nature. Some may argue this is reality of life. Perhaps.

Does four days work week possible? (via HN) Yes, either four-tens or you take a pay cut. Possible for those working in Asia region? Doubtful.

Which type of programmer you are? There are two types, starter and finisher.

Next.js? If you need a proper framework than the bare essential React. The frontend is so crowded and mess right now.

This Week I Learned 2018 - Week 02

Last week post or something recent from the past.

农历新年即将来临,在寻找适当的春联Antithetical couplet)时,偶然读到古代的「烟锁池塘柳」这上联,自古以来,难有适当的下联。但花燃山色用程序来寻找最佳的下联即搞笑又聪明。佩服!佩服!话说回来,历代比较好的对句如下:

  • 烟锁池塘柳,灯镶酒坊楼。
  • 烟锁池塘柳,炮镇海城楼。
  • 烟锁池塘柳,桃燃锦江堤。

After watching the demo on how to build your Javascript project using Webpack and Gulp. I'm seriously wonder what the eff have happened to the web development, especially the front end? While I'm for using latest development tools if possible, but the complexity of building and bundle the JavaScript rubs me the wrong way. Yes I know, once you get used to it and embrace it somehow. Where was the simple way of building web application?

When you're getting a new fish or plant to your tank, you will need to quarantine both. The issue with introducing new fishes or plants is that they may carry disease, fungus, and bacteria. Having a proper quarantine procedures also prevent potential pests (e.g. snails, insects, or worms) from being introduced to your tank. How we going to do that then? A teaspoon of aquarium salt and Methylene blue (a drop per gallon, depends). Vinita Phord have written a good introductory guide on the whole process. Adapt and adjust on your own.

Interesting talk given by a fellow data scientist who was originally a developer. Wish more young fresh graduates could join the talk. On the career side, the presenter gave tips on how to get yourself ready in data science. Three things: build enough competency, have confidence, and know enough to get it through. Always hire for the right reason, not just mere head counts. For young people, the most important criteria for selecting a job is the role is supportive to your career growth. Not just the salary, when you're fresh, pick the right environment to learn and contribute. Unfortunately, the talk was diverted into another old unresolved discussion or dispute of why we don't have enough lady in tech?

Fishackathon. Just realized this week that such even exists. The monitoring device in the 2016 winner team piqued my interest. Does a similar devices on a smaller scale exists in the market for hobbyist? Yes, there is Open Aquarium (based on Arduino) which is, unfortunately, costly and bulky.

Surprised to found that famous illustrator or comic artist, Chen Uen have passed away last year. Parka Blog have a review of his works. While I'm not a fan of his works, I firmly believe that Wuxia comics should definitely drawn in traditional Chinese painting style rather than the typical manga style.


This Week I Learned - 2017 Week 49

Last week post or something from the archive.

A few weeks ahead and we will reach the end of the year 2017 and embrace 2018. Slow week, lots of travelling and nothing much done. Interesting conversation with quite a few breeders.

Da Hu Fa is another good animation coming from China this year since the release of Big Fish & Begonia in 2016, preceded by Monkey King Hero Is Back in 2015. The Chinese animation industry comes a long way since the early days of Havoc in Heaven. It's still growing but still heavily influenced by Japanese anime in some ways and lack of the maturity and unique styles.

Interesting discussion on JavaScript itself with other developers. For RESTful API, use Koa.js (the development guide have some documentation), the next generation web framework for Node.js and the successor for Express.js.

Someone introduced me to Flow-based programming (FDP) and if you're using JavaScript, there is NoFlo. If you're from UNIX background, think FDP as pipeline or pipe and filter. Worth exploring and use it in your project? Well it depends, pretty much on the context or the type of system.



This Week I Learned - 2017 Week 46

Last week post or something from the archive. For something interesting related to a week, visualize your life in week. How many weeks do you still left?

So much things I've learned and observed this week. Some were the same old same old, others were quite eye opening instead, if you pay close attention.

Encountered this message, "expected, at character offset 2 (before "(end of string)")", when processing the JSON file during encoding. It turned out the root cause is how we use the read_file subroutine in File::Slurp module. Passing the right parameter, you can have multiple ways to either read the whole file or multiple lines. There even a research done on finding the optimized way to do do.

You’re working in the wrong place. (if you’re working in an open office)". When most of the employee are wearing headphones, that sufficiently shows that open floor plan have failed to reach its original intention, which to promote so-called information sharing and collaboration. Why open office don't work? Have you ever been to a library to study? If everyone keeps talking or making noise, do you think you can concentrate on your stuff?

The Amazing $1 Microcontroller. (via HN) The author should have written a book instead of a very lengthy blog post. I agree with the author, it's an exciting time for picking up electronic.

Looping through an array in JavaScript. A simple programming language construct, yet so many ways and workarounds. Add to that, you have JQuery way (.each()) of looping through DOM elements with its own quirk. Not to mention the let vs. var. No wonder so many JavaScript transpilers exists. And I was thinking PHP or Perl was bad, JavaScript is even more mind boggling. Forget about JavaScript, just stick to TypeScript which is gaining momentum these days.

The LEBRON stack. Anyone still remember the MEAN stack? I believe only Node.js survived the hype so far. Something similar, do you know Slack is using PHP for its server-side application logic?

Getting things done? (via HN) There are just two steps. However, till today, I'm still struggle with the execution of the system. Refine and more refine.

1/ Start something simple, the first step.
2/ You can stop if you want to.

This Week I Learned - 2016 Week 48

Last week post or the whole series.

December. How fast the time flies as we're approaching the end of the year 2016. Four more weeks to go and we will embrace the new year 2017. Yet, there is so much more to do here and there.

Full-text search (FTS) support for InnoDB was added in MySQL since version 5.6. While is a welcoming feature, especially those who don't want to use third party search engine like Sphinx or Apache Solr, there are still some default behaviours that you'll need to be aware of. First, there is this minimum and maximum word length to be indexed. By default, the minimum word length is three. If you need to produce results with two word length, consider adjusting the server settings and restart it later. Next, you can enable stop words being indexed. Stop words are common words in the language likes "the", "is', or others. Both settings are discussed here in good details.

Looking for FTS full examples, do look into Gutenberg book searching or song searching implementation. For a quick example, below SQL query is good enough for you to get started using FTS through multiple tables.
SELECT *, 
    MATCH(books.title) AGAINST('$q') as tscore,
    MATCH(authors.authorName) AGAINST('$q') as ascore,
    MATCH(chapters.content) AGAINST('$q') as cscore
FROM books 
LEFT JOIN authors ON books.authorID = authors.authorID 
LEFT JOIN chapters ON books.bookID = chapters.bookID 
WHERE 
    MATCH(books.title) AGAINST('$q')
    OR MATCH(authors.authorName) AGAINST('$q')
    OR MATCH(chapters.content) AGAINST('$q')
ORDER BY (tscore + ascore + cscore) DESC

On SQL. Sometimes the solution was so simple that we have overlook even the basic default feature. If you want to find the unique and maximum row by each group which sorted overall, the direct approach is just use MAX aggregate function. Example as shown below. Another approach is to use user variables, not my preference though.
SELECT t.client_id, MAX(t.points) AS "max"
FROM sessions t
GROUP BY t.client_id 
ORDERY BY MAX(t.points) DESC

Want to retain the order of the SQL query in your `IN()` operator? Use MySQL `FIELD()` function. Example as shown.
SELECT * FROM table ORDER BY FIELD(ID,1,5,4,3);

Perl Advent Calendar 2016 have started. I've mixed feeling regarding the first day post before Christmas. Till today, we still don't have a graphing feature built-in to visualize class relationships for any IDE out there for any less supported languages. And yet, we still needs to rely on Graphviz to visualize it. While Graphviz is an excellent tool, it lacking one crucial feature, better automatic diagram layout, something similar to yWorks' yFiles library.

Which Git workflow should you use? Gitlab have a discussion on different workflows. For me, master branch is always deployable approach seems to work for me. This HN user describes it succintly. Key points are:

1. Master branch is the deployable branch
2. All new features and developed in feature or topic branches.
3. Continiously rebase from master. Read this on resolving rebasing conflicts.
4. Send pull request for reviewing.
5. Testing is done in feature branches after rebasing from master and signed off from reviewer.
6. Feature branch is merged to master with a `--no-ff` (no fast foward). See diagram below.


The Github Flow is have the similar approach but the feature branch is deployed first before merge back to the master branch. The advantage of this approach is that you can always rollback to the master branch. Another variation is the Git flow, more complex with additional develop branch. Trunk-based development is another approach but I used before (another variation). However, I don't like the complexity introduced. Suitable if you have a dedicated release engineer.

Looking back at C++ again and I've no idea what I'm looking at. Why use typedefs to create alias for the default basic types? Portability. Implementing callbacks is a bit tricky, you really need to get over the C++ syntax used. Delegation in C++? Seriously, so many ways? All looks very hackish to me. Where is ? Didn't realize C++ don't have a ISO standard for quite some times. Undefined references? Most likely the order of the files being compiled causing linker problem.

Overwhelmed by front-end development works? The front-end scene is a moving target right now. There even a study plan to cure all these Javascript fatigue.

This Week I Learned - 2016 Week 43

Last week post or the whole series.

This is one of those week where I become very wordy. ;-)

Previous post was too long when I realized that Blogger don't let me add more than 20 tags. That threshold should be a good indicator for me to stop jotting down the item and move to next week post. Some of these notes below are old items which I haven't have time (lack of discipline) to jot it down in a timely manner (lack of consistency). Don't sweat on this. Reflect, learn, adapt, adjust, monitor, and continue as usual. Although there are some minor hiccups, there is still like 9 weeks to go for this year.

Generating and attached iCal invite through email? It may seems simple as first, but, as usual, it may works for one email client but not for others (we haven't take into consideration of desktop, mobile, and web client). Furthermore, there is iCal and vCal, both are VCALENDAR standard where the former is succesor of the later. Digging deeper, it seems that different email client behaves differently when come to REQUEST METHOD used. The typical troubleshooting procedure is first, make sure you can attach send the iCal correctly through email properly using the email library (using MIME::Lite in my case). Next, read other people code on implementing similar solution. You can may miss out certain API calls or use the library incorrectly.

Testing in Perl. You can go through these articles for a start before you jump in to Test Drive Deveopment (TDD) best practices. Some of the issues I've encountered. First, to compare two different different ordered arrays, `cmp_bag` in Test::Deep is your friend. Second, To simulate delay, instead of using `sleep`, you can use Test::Mocktime's `set_relative_time` to do so. But off course, you will need to learn more tricks about the default standard testing module in Perl, Test::More. Writing a new Perl's module, integrate testing as early as possible

While we on testing. To benchmark the speed of your SQL query, you can disable MySQL query cache. This ensure that no caching is used which may give the wrong impression regarding the speed of the query.

While this is quite old news, two features in Perl 5.10 which I think make a lot of senses. The `defined or` is useful to check if a variable is defined or else use the default value (more examples). And the `state` for declaring a variable as static variable. Useful when you want to implement localized caching.

On Perl again. Check if a substring exists in a string without using Regex through using `index`. I wish Perl have more Object-Oriented way of doing so. Maybe Perl 6 have it?

Note to self. This is very useful. Several alternative ways to monitoring event in Javascript, useful for debugging. My favourite is using the `monitorEvents($0)` method. So simple and straightforward.


While we're on Javascript. Developing a web application with heavy AJAX usages? Well, you have to use `history.pushState` somehow. Why not just switch to Turbolinks?

Storing hierarchical data in database? Adjacent List is the most common and first to use approach when modelling hierarchical tree. However, Bill Karwin's presentation and example and follow up example convinces me of using Closure Table or Bridge Table may be the balance and right approach. This is useful when you're using database system like MySQL that does not supports hierarchical and recursive SQL queries natively.


This Week I Learned - 2016 Week 39

Last week post or the whole series.

The month of October have started. As we're closing in to the end of year 2016, I've still have long list of pending items to follow up. Sometimes, is best to take break, reflecting on the current situation, and re-prioritize your short and long term goals. Nevertheless, there is one thing for sure, regardless the outcome, discipline is one sure way to get closer to what you want to achieve.

Interesting stuff I've learned this week.

Few days back, I've managed to finish the book Modern Perl. I bought and starting reading the book on 25th June and finished it by 30th September. It took me roughly 98 days to wrap up the whole book page by page (not a good strategy according to How to Read a Book). My impression? Not a beginner book and not quite a suitable book for any developer switching from other languages. It's more like a reference book on how to code according to the Modern Perl convention. The correct sequence of Perl books to read are as follow:

Language FundamentalsReferences
Learning Perl
Intermediate Perl
Mastering Perl
Programming Perl / the "Camel book"
Modern Perl

While we're in the discussion on book. I'm quite disappointed with Eloquent Javascript. Someone suggested that I should look into `You Don't Know JS` book series instead. Maybe I should try it out instead. It's currently the next item in my reading list.

Again, on Javascript. There is an annoying behaviour of using Array with Object. Seriously? I was caught surprised by this.

On a related note, the popularity of Javascript leads to an issue of Same-origin policy where it's not permitted to request a resource from different domain. The Cross-Origin Resource Sharing (CORS) is a specification to resolve this. Solution exists for different popular web servers with support from different web browsers. For example, how to resolve this matter in Cloudfront.

Life as a Middle-Aged Geek (via HN). The advantage of being a middle-age developer is you probably know what you want or don't want out of your life. As time is catching up and you have plenty of life commitments elsewhere, if better you should constantly review and revise your own life goals. While ageism is an ongoing issue with technology sector, the Old Geek Jobs site was created for those developers whose are (35 and beyond). Or you can be an indie hacker instead?

Look-and-say sequence. Quite an interesting integer sequence, useful when you want to setup a new Wifi password but at the same time, want to confuse the hell of your users.

TLD used for local development? Mine is still using `.dev` but you must be aware that `.dev` is a generic Top Level Domain (gTLD).

Differences between Ansible's `command` and `shell` usages and when to use it. It seems I need to rewrite most of my dotfiles' steps. Didn't realize that `ansible-lint` actual exists.

What are the software stacks or cool tools used in the startup scene?

How to hire a programmer? While technical skills is a crucial requirement, cultural fit and attitude are equivalent important as well. But, as the article mentioned, nothing is guaranteed.

This Week I Learned - 2016 Week 38

Last week post or the whole series. Interesting stuff learned this week.

Encountered this error message when checking a USB thumbdrive with `fdisk` command. The particular thumb drive was burned with an ISO file through the `dd` command.
$ sudo fdisk -l
......
GPT PMBR size mismatch (1432123 != 15765503) will be corrected by w(rite).
Disk /dev/sdc: 7.5 GiB, 8071938048 bytes, 15765504 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 8C18967D-CB41-4EF1-8958-4E495054958D

Device     Start     End Sectors   Size Type
/dev/sdc1     64   17611   17548   8.6M Microsoft basic data
/dev/sdc2  17612   23371    5760   2.8M EFI System
/dev/sdc3  23372 1432075 1408704 687.9M Microsoft basic data

Follow the instructions given, running the device through `gparted` seems to resolve the issue.



Perl's hash initialization, referencing, and de-referencing. Seriously, I need to get this correctly and read more Perl's FAQs.
# Normal way, without referencing.
%foobar = (a => '1', b => '2');
say $foobar{a};

# Using referencing. More readable.
$foobar = {a => '1', b => '2'};
say $foobar->{a};

# Alternatively.
$foobar_ref = \%foobar;
say $foobar_ref->{a};

Finding properties of the event target in Javascript.
$('foo').bind('click', function () {
    // inside here, `this` will refer to the foo that was clicked
});

How do you add a trailing slash if none found? Regex, regex.
$string =~ s!/*$!/!; # Add a trailing slash

Protocol-relative URL. While we're on HTTP protocol, it was made aware to me that the anchor tag should be the last item on the URL.

CSS image sprite technique using HTML unordered list. One of the issue encountered is if you have single line text link, how do you align the text link vertically in the middle? Make sure the `line-height` is equal to `height` for the `li`` element.

Git merge conflict? Just abort the whole process.

Similarly discard all changes on a diverged local branch, two ways. First method is to my liking.
# Method 1
$ git branch -D phobos
$ git checkout --track -b phobos origin/phobos

# Method 2
$ git checkout phobos
$ git reset --hard origin/phobos

Debugging Dockerfile. Something I learned this week but in a separate and longer post.

Starting a new software project but not sure about which technology stack to use? Read this slide as a guide.






This Week I Learned - 2016 Week 37

Last week post or the whole series.

As we're moving to the end of the third quarter of the year, more things pop up for me to follow up. Interestingly but not surprisingly, life is as monotonous as ever. Yes, it can be routinely, but that probably the only way, through sheer discipline, to follow through your plans.

The components for setting up my homelab using AMD 5350 have been bought and set up accordingly. The only remaining tasks is to install the necessary OS and configuration. More writeups on this in coming future.

As usual, something I learned this week.

Looking into Makefile, specifically GNU MakeExtracting parameters from target? Yes, is doable but it's not pretty. See code below. If your target is not an actual physical file, make it a '.PHONY' target instead. Otherwise you will encounter "No rule to make target" error. Next, we will need to 'eval' when extracting the assigning the parameters passed, otherwise the 'PARAMS' assignment will be executed as command.
.PHONY: action

action:
    $(eval PARAMS := $(filter-out [email protected],$(MAKECMDGOALS)))
    @echo $(PARAMS)

Interestingly, there are four ways for variable assignment in Make. The 'Set If Absent' way of variable declaration and initialization is quite handly. Funny though, Perl, which is known for its brevity, does not have such language construct.
# Lazy Set. Value is expanded and set when used.
FOOBAR = x

# Immediate Set. Value is set when declared.
FOOBAR := x

# Set If Absent
FOOBAR ?= x

# Append
FOOBAR += x

Write it down, make it happens. Never underestimate the power of writing. Sometimes, the pen is mightier than the sword.

'git commit --allow-empty'. My goodness! I'm not aware of this option exists in Git. How many times I've adjusted a space just to create and make an empty dummy commit. While we on Git, if you seems to "misuse" it somehow, there are many ways to recover back.

Web development is a layer of layer of layer of abstraction hacks? I firmly believe. It's messy, plagues with multiple choices, and feels like wild wild west. HN user, meredydd mentioned that modern web application today consists of five programming languages and three frameworks. Interestingly, I never realize there are so many choices. Maybe future Javascript, ES2016 can reduce that paradox of choices by standardizing on using the same language for frontend and backend, as in isomorphic Javascript? But that also raises another interesting question. Is web development a constant rewrite of existing application to newer technologies?