Unfortunately, each of these systems is highly complex and can inflict all kinds of damage on data, much of the damage undetectable to humans.

You're checking state in a mailer

It's going to be so fun to scale when you finally want to add more unsubscribe links for different types of sequences

If you have anything like this is your codebase, you need Caffeinate:

What is the Docker host filesystem owner matching problem?

Using Time.now (which returns the wall-clock time) as base-lines has a couple of issues which can result in unexpected behavior. This is caused by the fact that the wallclock time is subject to changes like inserted leap-seconds or time slewing to adjust the local time to a reference time. If there is e.g. a leap second inserted during measurement, it will be off by a second. Similarly, depending on local system conditions, you might have to deal with daylight-saving-times, quicker or slower running clocks, or the clock even jumping back in time, resulting in a negative duration, and many other issues. A solution to this issue is to use a different time of clock: a monotonic clock.

Email addresses sometimes get reassigned to a different person. For example, employment changes at a company can cause an address used for an ex-employee to be assigned to a new employee, or a mail service provider (MSP) might expire an account and then let someone else register for the local-part that was previously used. Those who sent mail to the previous owner of an address might not know that it has been reassigned. This can lead to the sending of email to the correct address but the wrong recipient. This situation is of particular concern with transactional mail related to purchases, online accounts, and the like.

Today, many web developers are even using JavaScript's native module syntax, but combining it with bare import specifiers, thus making their code unable to run on the web without per-application, ahead-of-time modification. We'd like to solve that, and bring these benefits to the web.

I am not looking for model based after commits on update/create/etc, I want to be able to dynamically define a block that will be executed only if the current (top-most) transaction passes:

Making one Comment query per Post is too expensive; it’s N+1 queries (one to fetch the posts, N to fetch the comments). You could use includes to preload all the comments for all the posts, but that requires hydrating hundreds of thousands of records, even though you only need a few hundred for your front page. What you want is some kind of GROUP BY with a LIMIT on each group — but that doesn’t exist, either in Activerecord nor even in postgres. Postgres has a different solution for this problem: the LATERAL JOIN.

Its goal is to solve the problems with downloading templates to start your app from:

What seems more problematic is divergence between drivers. For example, capybara-webkit and poltergeist support several of the same things. Let's take resizing the window as an example. In capybara-webkit this is page.driver.resize_window(x, y) and in poltergeist it's page.driver.resize(x, y). This means that if a user wants to switch from one to the other they have to change their code. Now I don't know if selenium does or doesn't support resizing the window, but supposing it doesn't I think there's still a lot of value in the capybara project deciding what the blessed API is, because then all the drivers that support that feature can implement it using the same API, increasing portability.

The goal of this technology is to provide a mechanism for browser-based applications that need two-way communication with servers that does not rely on opening multiple HTTP connections (e.g., using XMLHttpRequest or <iframe>s and long polling).

To illustrate the problem:

Most programming languages vend environment variables as strings. This leads to errors like so:

I’m going to add the API Server as an actor to my first test sequence to give some granularity as to what I’m actually testing.

Instead of having this confusing maze of lambdas, regexes, and strings, we could, in theory, introduce a single entry point of configuration for Sprockets to use, and in that file declare all assets we wanted to compile. Well, that’s exactly what the manifest.js file is.

This can be useful in cases like multistep registration. Previously in # rails we used to stick all of the validations in the class and then we're # stuck validating them all everytime

However, sometimes actions can't be rolled back and it is unfortunately unavoidable. For example, consider when we send emails during the call to process. If we send before saving a record and that record fails to save what do we do? We can't unsend that email.

But it doesn't work so I have to wrap slots in useless and interfering divs or spans like this: <Button fz="16" h="64" {...$$props}> <span slot="prepend"><slot name="prepend" /></span> <slot /> <span slot="append"><slot name="append" /></span> </Button>

Say I have a separate API server that provides content for a Sapper route. I could just query that API in my route's preload function, but if the content changes rarely, I don't want to incur that cost for every page load and would much rather cache responses from the API on the Sapper side.

This is an opportunity to fix a bug: if you're on a page that redirects to a login page if there's no user object, or otherwise preloads data specific to that user, then logging out won't automatically update the page — you could easily end up with a page like HOME ABOUT LOG IN ----------------------------------------------------------------------------------------- Secret, user-specific data that shouldn't be visible alongside a 'log in' button:

This pattern can be neater syntactically because declaring a variable in a try block with let scopes the variable to the try block.

So, how does an SPA work? JavaScript loads in the browser and loads data from an API. Most of the rendering is done on the client Side. But search engine bots have a hard time indexing the page because it doesn't have much without JS.

This scenario demonstrates one drawback of CSS: With all the style rules that need to be applied to multiple elements on multiple pages, things can get pretty redundant. And redundancy can eat up your time and cause friction whenever you need to change a color, font, or any other style aspect across your site.

true && { echo true; false; } || { echo false; true; }

Examples of this include: requiring base classes or reading from imported variables that have not been initialized yet.

as soon as you have a (indirect) circular dependency, you might be interacting with a half loaded module in your code.

You can see that behaviour in this example. Select a range of text and hit the tab key. Because the <textarea> value changes, the current selection is cleared and the cursor jumps, annoyingly, to the end.

Just like elements can have children... <div> <p>I'm a child of the div</p> </div>...so can components. Before a component can accept children, though, it needs to know where to put them. We do this with the <slot> element.

The primary motivation behind virtual-dom is to allow us to write code independent of previous state. So when our application state changes we will generate a new VTree. The diff function creates a set of DOM patches that, based on the difference between the previous VTree and the current VTree, will update the previous DOM tree to match the new VTree.

Manual DOM manipulation is messy and keeping track of the previous DOM state is hard. A solution to this problem is to write your code as if you were recreating the entire DOM whenever state changes. Of course, if you actually recreated the entire DOM every time your application state changed, your app would be very slow and your input fields would lose focus.

Before MDX, some of the benefits of writing Markdown were lost when integrating with JSX. Implementations were often template string-based which required lots of escaping and cumbersome syntax.

Part of why most code -- and most software -- sucks so much is that making sweeping changes is hard.

Why

However imagine we are creating a format string in a separate file, commonly because we would like to internationalize it and we rewrite it as: <?php$format = 'The %s contains %d monkeys';echo sprintf($format, $num, $location);?> We now have a problem. The order of the placeholders in the format string does not match the order of the arguments in the code. We would like to leave the code as is and simply indicate in the format string which arguments the placeholders refer to. We would write the format string like this instead: <?php$format = 'The %2$s contains %1$d monkeys';echo sprintf($format, $num, $location);?> An added benefit is that placeholders can be repeated without adding more arguments in the code.

$format = 'There are %d monkeys in the %s';

$format = 'The %s contains %d monkeys'

Poedit and other tools can scan your .php files for references of __(), _e(), _n() and so on, and grab those strings for translation, which is awesome, because otherwise you’d have to manually add every single string. Now, when these tools come across _n() in our sources, they know it’s a plural thing, because of a special keyword setting which looks something like _n:1,2, meaning _n() takes at least two arguments, where the first argument is the singular, and the second argument is a the plural, so it grabs both strings. Let’s take a look at how Poedit and other tools will parse our function above: Hello there _n() on line 3! I’m supposed to grab two of your arguments because I have this smart keyword setting, but none of these arguments are strings, so I’ll just skip to the next match

Nix helps you make sure that package dependency specifications are complete. In general, when you’re making a package for a package management system like RPM, you have to specify for each package what its dependencies are, but there are no guarantees that this specification is complete. If you forget a dependency, then the component will build and work correctly on your machine if you have the dependency installed, but not on the end user's machine if it's not there.

You might be thinking––"a tool that allows me to write semantic and reusable queries? Sounds like Active Record". It's absolutley true that Active Record already provides a powerful query tool kit. But what happens when even simple queries stretch the bounds of Active Record's capabilities?

Such verbose. Much code. Very bloat. Wow. We've lost all the awesome association introspection that ActiveRecord would otherwise have given us.

But it's not easy to open todo.txt, make a change, and save it—especially on your touchscreen device and at the command line. Todo.txt apps solve that problem.

Sometimes cronjobs fail to run successfully because a required server (like a database or ftp server) is temporarily unavailable due to power failures, hardware failures, software failures, network outages, choice of operating system, pilot error, and the like. Typically, this results in someone being forced to examine crontabs and error reports, determine which cronjobs really need to be run, and then run them manually. This happened to me twice in one week. I don't want it to happen again. Cronjobs are meant to be automated and I want them to stay that way. This is the rationale for noexcuses.

An ssh public key in a ~/.ssh/authorized_keys file can have a command="" option which forces a particular command to be executed when the key is used to authenticate an ssh connection. This is a security control that mitigates against private key compromise. This is great when you only need to execute a single command. But if you need to perform multiple tasks, you would normally need to create and install a separate key pair for each command, or just not bother making use of forced commands and allow the key to be used to execute any command.

However, these benefits only accrue to outbound connections made from the local system to ssh servers elsewhere: once logged into a remote server, connecting from there to yet a third server requires either password access, or setting up the user's private key on the intermediate system to pass to the third. Having agent support on the local system is certainly an improvement, but many of us working remotely often must copy files from one remote system to another. Without installing and initializing an agent on the first remote system, the scp operation will require a password or passphrase every time. In a sense, this just pushes the tedium back one link down the ssh chain.

You might want developers building projects with this CMS to be able to change the behaviour of some UIs, or to be able to provide new components that can be consumed by the CMS. Those components can't easily be included in the JS bundle for the CMS, as it would require recompiling the shipped code with outside references.

However, again you would have to lift state up to the App component in order to pass the amount to the currency components. As you can see, the component composition on its own doesn't help us to solve the problem. That's the point where React's render props pattern comes into play which enhances React's component composition with an important ingredient: a render function.