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.prettierrc.json
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{
"singleQuote": true
"singleQuote": true,
"proseWrap": "always"
}

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LICENSE.md
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Copyright 2020-2024 Morris Brodersen <mb@morrisbrodersen.de>
Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.
Permission to use, copy, modify, and/or distribute this software for any purpose
with or without fee is hereby granted, provided that the above copyright notice
and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
THIS SOFTWARE.

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# VANILLA TODO
A [TeuxDeux](https://teuxdeux.com) clone in plain HTML, CSS and JavaScript
(no build steps). It's fully animated and runs smoothly at 60 FPS
with a total transfer size of **55 KB** (unminified).
A [TeuxDeux](https://teuxdeux.com) clone in plain HTML, CSS and JavaScript (no
build steps). It's fully animated and runs smoothly at 60 FPS with a total
transfer size of **55 KB** (unminified).
**[Try it online →](https://morris.github.io/vanilla-todo/)**
More importantly, it's a case study showing that **vanilla web development** is
viable in terms of [maintainability](#521-the-good),
and worthwhile in terms of [user experience](#51-user-experience)
(**50%** less time to load and **95%** less bandwidth in this case).
viable in terms of [maintainability](#521-the-good), and worthwhile in terms of
[user experience](#51-user-experience) (**50%** less time to load and **95%**
less bandwidth in this case).
**There's no custom framework invented here.**
Instead, the case study was [designed](#22-rules) to discover
minimum viable [patterns](#321-mount-functions) that are truly vanilla.
The result is maintainable, albeit [verbose](#522-the-verbose) and with
considerable duplication.
**There's no custom framework invented here.** Instead, the case study was
[designed](#22-rules) to discover minimum viable
[patterns](#321-mount-functions) that are truly vanilla. The result is
maintainable, albeit [verbose](#522-the-verbose) and with considerable
duplication.
If anything, the case study validates the value of build steps and frameworks,
but also demonstrates that standard web technologies can be used effectively and
there are only a few [critical areas](#523-the-bad) where a vanilla approach is
clearly inferior.
_While the first version of the case study has been published in 2020, it has received significant [updates](#9-changelog) over time._
_While the first version of the case study has been published in 2020, it has
received significant [updates](#9-changelog) over time._
_Intermediate understanding of the web platform is required to follow through._
@ -68,22 +69,20 @@ _Intermediate understanding of the web platform is required to follow through._
## 1. Motivation
I believe too little has been invested in researching
practical, scalable methods for building web applications
without third party dependencies.
I believe too little has been invested in researching practical, scalable
methods for building web applications without third party dependencies.
It's not enough to describe how to create DOM nodes
or how to toggle a class without a framework.
It's also rather harmful to write an article
saying you don't need library X, and then proceed in describing how
to roll your own untested, inferior version of X.
It's not enough to describe how to create DOM nodes or how to toggle a class
without a framework. It's also rather harmful to write an article saying you
don't need library X, and then proceed in describing how to roll your own
untested, inferior version of X.
What's missing are thorough examples of complex web applications
built only with standard web technologies, covering as many aspects of
the development process as possible.
What's missing are thorough examples of complex web applications built only with
standard web technologies, covering as many aspects of the development process
as possible.
This case study is an attempt to fill this gap, at least a little bit,
and inspire further research in the area.
This case study is an attempt to fill this gap, at least a little bit, and
inspire further research in the area.
## 2. Method
@ -99,16 +98,16 @@ This section describes the method in more detail.
### 2.1. Subject
I've chosen to build a (functionally reduced) clone of
[TeuxDeux](https://teuxdeux.com) for this study.
The user interface has interesting challenges,
in particular performant drag & drop when combined with animations.
[TeuxDeux](https://teuxdeux.com) for this study. The user interface has
interesting challenges, in particular performant drag & drop when combined with
animations.
_The original TeuxDeux app deserves praise here. In my opinion it has the
best over-all concept and UX of all the to-do apps out there.
_The original TeuxDeux app deserves praise here. In my opinion it has the best
over-all concept and UX of all the to-do apps out there.
[Thank you!](https://fictivekin.com/)_
The user interface is arguably small (which is good for a case study)
but large enough to require thought on its architecture.
The user interface is arguably small (which is good for a case study) but large
enough to require thought on its architecture.
However, it is lacking in some key areas:
@ -119,8 +118,8 @@ However, it is lacking in some key areas:
### 2.2. Rules
To produce valid vanilla solutions, and because constraints spark creativity,
I came up with a set of rules to follow throughout the process:
To produce valid vanilla solutions, and because constraints spark creativity, I
came up with a set of rules to follow throughout the process:
- Only use standard web technologies.
- Only use widely supported JS features unless they can be polyfilled (1).
@ -130,9 +129,9 @@ I came up with a set of rules to follow throughout the process:
(1) This is a moving target; the current version is using ES2020.
(2) These usually end up becoming a custom micro-framework,
thereby questioning why you didn't use one of the
established and tested libraries/frameworks in the first place.
(2) These usually end up becoming a custom micro-framework, thereby questioning
why you didn't use one of the established and tested libraries/frameworks in the
first place.
### 2.3. Goals
@ -140,75 +139,73 @@ The results are going to be assessed by three major concerns:
#### 2.3.1. User Experience
The product should be comparable to or better
than the original regarding functionality, performance and design.
The product should be comparable to or better than the original regarding
functionality, performance and design.
This includes testing major browsers and devices.
#### 2.3.2. Code Quality
The implementation should be _maintainable_ and
follow established code quality standards.
The implementation should be _maintainable_ and follow established code quality
standards.
This will be difficult to assess objectively, as we will see later.
#### 2.3.3. Generality of Patterns
The discovered techniques and patterns should be applicable in a wide
range of scenarios.
The discovered techniques and patterns should be applicable in a wide range of
scenarios.
## 3. Implementation
This section walks through the implementation, highlighting techniques
and problems found during the process. You're encouraged to inspect the
This section walks through the implementation, highlighting techniques and
problems found during the process. You're encouraged to inspect the
[source code](./public) alongside this section.
### 3.1. Basic Structure
Since build steps are ruled out, the codebase consists of
plain HTML, CSS and JS files. The HTML and CSS follows
[rscss](https://ricostacruz.com/rscss/) (devised by [Rico Sta. Cruz](https://ricostacruz.com))
resulting in an intuitive, component-oriented structure.
Since build steps are ruled out, the codebase consists of plain HTML, CSS and JS
files. The HTML and CSS follows [rscss](https://ricostacruz.com/rscss/) (devised
by [Rico Sta. Cruz](https://ricostacruz.com)) resulting in an intuitive,
component-oriented structure.
The stylesheets are slightly verbose.
[CSS variables](https://developer.mozilla.org/en-US/docs/Web/CSS/Using_CSS_custom_properties)
did help but I missed [SCSS](https://sass-lang.com/) here;
I think it's a must-have for bigger projects.
Additionally, the global CSS namespace problem is unaddressed
(see e.g. [CSS Modules](https://github.com/css-modules/css-modules)).
did help but I missed [SCSS](https://sass-lang.com/) here; I think it's a
must-have for bigger projects. Additionally, the global CSS namespace problem is
unaddressed (see e.g.
[CSS Modules](https://github.com/css-modules/css-modules)).
All JavaScript files are ES modules (`import`/`export`).
I added a few
All JavaScript files are ES modules (`import`/`export`). I added a few
[JSDoc](https://www.typescriptlang.org/docs/handbook/jsdoc-supported-types.html)
comments to functions to get additional code completion in VSCode.
This helps, but using TypeScript would be much safer and less verbose.
comments to functions to get additional code completion in VSCode. This helps,
but using TypeScript would be much safer and less verbose.
Note that I've opted out of web components completely.
My attempts to refactor the implementation using web components
either added more complexity, or did not show significant value
over the initial, more basic approach.
Note that I've opted out of web components completely. My attempts to refactor
the implementation using web components either added more complexity, or did not
show significant value over the initial, more basic approach.
---
The basic structure comes with some boilerplate,
e.g. referencing all the individual stylesheets and scripts from the HTML;
probably enough to justify a simple build step.
The basic structure comes with some boilerplate, e.g. referencing all the
individual stylesheets and scripts from the HTML; probably enough to justify a
simple build step.
It is otherwise straight-forward&mdash;literally a bunch of HTML, CSS and JS files.
It is otherwise straight-forward&mdash;literally a bunch of HTML, CSS and JS
files.
### 3.2. JavaScript Architecture
Naturally, the JavaScript architecture is the most interesting part of this study.
Naturally, the JavaScript architecture is the most interesting part of this
study.
I found that using a combination of functions,
query selectors and DOM events is sufficient
to build a scalable, maintainable codebase,
albeit with some trade-offs as we will see later.
I found that using a combination of functions, query selectors and DOM events is
sufficient to build a scalable, maintainable codebase, albeit with some
trade-offs as we will see later.
Conceptually, the proposed architecture loosely maps
CSS selectors to JS functions which are _mounted_ (i.e. called) once
per matching element. This simple mental model aligns well
with the DOM and styles:
Conceptually, the proposed architecture loosely maps CSS selectors to JS
functions which are _mounted_ (i.e. called) once per matching element. This
simple mental model aligns well with the DOM and styles:
```
TodoList -> .todo-list
@ -227,9 +224,9 @@ implementation process.
#### 3.2.1. Mount Functions
_Mount functions_ take a DOM element as their first argument.
Their responsibility is to set up initial state, event listeners, and
provide behavior and rendering for the target element.
_Mount functions_ take a DOM element as their first argument. Their
responsibility is to set up initial state, event listeners, and provide behavior
and rendering for the target element.
For example, this mount function implements a simple counter:
@ -290,13 +287,13 @@ export function MyCounter(el) {
document.querySelectorAll('.my-counter').forEach(MyCounter);
```
This comes with quite some boilerplate but has useful properties,
as we will see in the following sections.
This comes with quite some boilerplate but has useful properties, as we will see
in the following sections.
Note that a mount function does not have to set any base HTML,
and may instead only set event listeners to enable some behavior.
Also note that an element can be mounted with multiple mount functions.
For example, to-do items are mounted with `TodoItem` and `AppDraggable`.
Note that a mount function does not have to set any base HTML, and may instead
only set event listeners to enable some behavior. Also note that an element can
be mounted with multiple mount functions. For example, to-do items are mounted
with `TodoItem` and `AppDraggable`.
Compared to React components, mount functions provide interesting flexibility as
components and behaviors can be implemented using the same idiom and combined
@ -313,28 +310,26 @@ Reference:
I found it effective to implement one-way data flow similar to React's approach,
however exclusively using custom DOM events.
- **Data flows downwards** from parent components to child components
through custom DOM events. Data events are in noun-form.
- **Actions flow upwards** through custom DOM events (bubbling up),
usually resulting in some parent component state change which is in turn
propagated downwards through data events. Action events are in verb-form.
- **Data flows downwards** from parent components to child components through
custom DOM events. Data events are in noun-form.
- **Actions flow upwards** through custom DOM events (bubbling up), usually
resulting in some parent component state change which is in turn propagated
downwards through data events. Action events are in verb-form.
The business logic is factored into a pure functional core
([TodoLogic.js](./public/scripts/TodoLogic.js)).
This is a sensible approach in most UI architectures as it encapsulates
state transitions in portable, testable units.
([TodoLogic.js](./public/scripts/TodoLogic.js)). This is a sensible approach in
most UI architectures as it encapsulates state transitions in portable, testable
units.
The controller is factored into a separate behavior
([TodoController.js](./public/scripts/TodoController.js)).
It only receives and dispatches events,
calling the business logic to apply changes and emit state.
([TodoController.js](./public/scripts/TodoController.js)). It only receives and
dispatches events, calling the business logic to apply changes and emit state.
It also handles persistence in Local Storage.
Listening to and dispatching events is slightly verbose with standard APIs and
certainly justifies introducing helpers.
I didn't need event delegation à la jQuery for this study
but I believe it's a useful concept that is difficult to do
concisely with standard APIs.
certainly justifies introducing helpers. I didn't need event delegation à la
jQuery for this study but I believe it's a useful concept that is difficult to
do concisely with standard APIs.
Reference:
@ -344,8 +339,8 @@ Reference:
#### 3.2.3. Rendering
Naively re-rendering a whole component using `.innerHTML` should be avoided
as this may hurt performance and will likely break important functionality like:
Naively re-rendering a whole component using `.innerHTML` should be avoided as
this may hurt performance and will likely break important functionality like:
- `<a>`, `<button>`, `<input>`, etc. may lose focus.
- Form inputs may lose data.
@ -357,18 +352,17 @@ As seen in [3.2.1.](#321-mount-functions), rendering is therefore split into
some rigid base HTML and an idempotent, complete update function which only
makes necessary changes.
- **Idempotence:** Update functions may be called at any time
and should always render the component correctly.
- **Completeness:** Update functions should render
the whole component, regardless of what triggered the update.
- **Idempotence:** Update functions may be called at any time and should always
render the component correctly.
- **Completeness:** Update functions should render the whole component,
regardless of what triggered the update.
In effect, this means almost all DOM manipulation is done in update functions,
which greatly contributes to robustness and readability of the codebase.
As seen above this approach is quite verbose and ugly compared to JSX, for
example. However, it's very performant and can be further optimized
by checking for data changes, caching selectors, etc.
It is also simple to understand.
example. However, it's very performant and can be further optimized by checking
for data changes, caching selectors, etc. It is also simple to understand.
Reference:
@ -377,9 +371,9 @@ Reference:
#### 3.2.4. Reconciliation
Expectedly, the hardest part of the study was rendering a variable
amount of dynamic components efficiently. Here's a commented example
from the implementation outlining the reconciliation algorithm:
Expectedly, the hardest part of the study was rendering a variable amount of
dynamic components efficiently. Here's a commented example from the
implementation outlining the reconciliation algorithm:
```js
export function TodoList(el) {
@ -441,32 +435,30 @@ export function TodoList(el) {
}
```
It's very verbose, with lots of opportunities to introduce bugs.
Compared to a simple loop in JSX, this approach seems unreasonable.
It is quite efficient as it does minimal work, but it's
definitely a candidate for a utility function or library.
It's very verbose, with lots of opportunities to introduce bugs. Compared to a
simple loop in JSX, this approach seems unreasonable. It is quite efficient as
it does minimal work, but it's definitely a candidate for a utility function or
library.
### 3.3. Drag & Drop
Implementing drag & drop from scratch was challenging,
especially regarding browser/device consistency.
Implementing drag & drop from scratch was challenging, especially regarding
browser/device consistency.
Using a library would have been a lot more cost-effective initially.
However, having a customized implementation paid off once I started
introducing animations as both had to be coordinated closely.
I can imagine this would have been a difficult problem
when using third party code for either.
Using a library would have been a lot more cost-effective initially. However,
having a customized implementation paid off once I started introducing
animations as both had to be coordinated closely. I can imagine this would have
been a difficult problem when using third party code for either.
The drag & drop implementation is (again) based on DOM events and integrates
well with the remaining architecture.
It's clearly the most complex part of the study but I was able to implement it
without changing existing code besides mounting behaviors and
adding event handlers.
well with the remaining architecture. It's clearly the most complex part of the
study but I was able to implement it without changing existing code besides
mounting behaviors and adding event handlers.
I suspect the drag & drop implementation to have some subtle problems on
touch devices, as I haven't extensively tested them. Using a library for
identifying the gestures could be more sensible and would reduce costs in
testing browsers and devices.
I suspect the drag & drop implementation to have some subtle problems on touch
devices, as I haven't extensively tested them. Using a library for identifying
the gestures could be more sensible and would reduce costs in testing browsers
and devices.
Reference:
@ -478,15 +470,14 @@ Reference:
For the final product I wanted smooth animations for most user interactions.
This is a cross-cutting concern which was implemented using the
[FLIP](https://aerotwist.com/blog/flip-your-animations/) technique as devised
by [Paul Lewis](https://twitter.com/aerotwist).
[FLIP](https://aerotwist.com/blog/flip-your-animations/) technique as devised by
[Paul Lewis](https://twitter.com/aerotwist).
Implementing FLIP animations without a large refactoring was the biggest
challenge of this case study, especially in combination with drag & drop.
After days of work I was able to implement the algorithm in isolation and
coordinate it with other concerns at the application's root level.
The `useCapture` mode of `addEventListener` proved to be very useful
in this case.
challenge of this case study, especially in combination with drag & drop. After
days of work I was able to implement the algorithm in isolation and coordinate
it with other concerns at the application's root level. The `useCapture` mode of
`addEventListener` proved to be very useful in this case.
Reference:
@ -495,10 +486,11 @@ Reference:
## 4. Tooling
While no runtime dependencies or build steps were allowed,
I did introduce some local tooling to support the development experience.
While no runtime dependencies or build steps were allowed, I did introduce some
local tooling to support the development experience.
As a quick start, here are the steps to get a local development server up and running:
As a quick start, here are the steps to get a local development server up and
running:
- Install [git](https://git-scm.com/)
- Install [Node.js](https://nodejs.org/) (>= 20)
@ -513,34 +505,32 @@ The following sections describe the tooling in more detail.
### 4.1. Local Development Server
Because ES modules are not allowed under the `file://` protocol
I needed to run a local web server for development.
Initially, I used [serve](https://www.npmjs.com/package/serve)
which was good enough to get going but requires manually reloading
the application on every change.
Because ES modules are not allowed under the `file://` protocol I needed to run
a local web server for development. Initially, I used
[serve](https://www.npmjs.com/package/serve) which was good enough to get going
but requires manually reloading the application on every change.
Most modern frameworks support _hot reloading_,
i.e. updating the application in place when changing source files.
Hot reloading provides fast feedback during development,
especially useful for fine-tuning visuals.
Most modern frameworks support _hot reloading_, i.e. updating the application in
place when changing source files. Hot reloading provides fast feedback during
development, especially useful for fine-tuning visuals.
Unfortunately, I could not find a local development server
supporting some form of hot reloading
without introducing a framework or build system,
but I was able to implement a minimal local development server (~200 LOC)
with the following behavior:
Unfortunately, I could not find a local development server supporting some form
of hot reloading without introducing a framework or build system, but I was able
to implement a minimal local development server (~200 LOC) with the following
behavior:
- Changes to stylesheets or images will hot replace the changed resources.
- Other changes (e.g. JavaScript or HTML) will cause a full page reload.
While it's not proper [hot module replacement](https://webpack.js.org/concepts/hot-module-replacement/)
(which requires immense infrastructure),
it requires zero changes to the application source
and provides a similar experience because page reloads are fast.
While it's not proper
[hot module replacement](https://webpack.js.org/concepts/hot-module-replacement/)
(which requires immense infrastructure), it requires zero changes to the
application source and provides a similar experience because page reloads are
fast.
Note that the local development server is highly experimental and is likely lacking
some features to be generally usable. See [/dev](./dev) for the implementation.
Feedback is highly appreciated.
Note that the local development server is highly experimental and is likely
lacking some features to be generally usable. See [/dev](./dev) for the
implementation. Feedback is highly appreciated.
### 4.2. Formatting and Linting
@ -550,8 +540,8 @@ Basic code consistency is provided by
- [ESLint](https://eslint.org), and
- [stylelint](https://stylelint.io).
I've set the ESLint parser to ES2020 to ensure only ES2020 code is allowed.
I've also added stylelint rules to check for rscss-compatible CSS.
I've set the ESLint parser to ES2020 to ensure only ES2020 code is allowed. I've
also added stylelint rules to check for rscss-compatible CSS.
Run these commands to try it out:
@ -565,18 +555,18 @@ integrate well with VSCode so I've rarely had to run these manually.
### 4.3. Testing
I've implemented some end-to-end and unit tests
using [Playwright](https://playwright.dev/).
While running a local web server (see above), you can run the tests with
I've implemented some end-to-end and unit tests using
[Playwright](https://playwright.dev/). While running a local web server (see
above), you can run the tests with
- `npm run test` for headless tests, or
- `npm run test-ui` for interactive mode.
These might ask you to install Playwright; just follow the instructions.
There's a lot more to explore here, but it's not much different from
testing other frontend stacks. It's actually simpler as there was zero
configuration and just one dependency.
There's a lot more to explore here, but it's not much different from testing
other frontend stacks. It's actually simpler as there was zero configuration and
just one dependency.
Reference:
@ -587,15 +577,14 @@ Reference:
I was able to set up code coverage (at least for end-to-end tests) via
[Playwright's code coverage feature](https://playwright.dev/docs/api/class-coverage)
and [c8](https://github.com/bcoe/c8).
This introduced another dependency and was slightly more involved to get right,
e.g. mapping localhost URLs to file URLs.
and [c8](https://github.com/bcoe/c8). This introduced another dependency and was
slightly more involved to get right, e.g. mapping localhost URLs to file URLs.
Use `npm run test-coverage` to run the tests and produce an LCOV test coverage
report in `./coverage`.
Note that the implementation is specific to the project structure,
e.g. `/public` as web root and port `8080` are hard-coded.
Note that the implementation is specific to the project structure, e.g.
`/public` as web root and port `8080` are hard-coded.
Reference:
@ -604,9 +593,9 @@ Reference:
### 4.4. Pipeline
I've added a simple CI/CD pipeline via GitHub Actions.
It runs linters and tests, and deploys to GitHub Pages on success.
This was straight-forward and is orthogonal to the application code and other tooling.
I've added a simple CI/CD pipeline via GitHub Actions. It runs linters and
tests, and deploys to GitHub Pages on success. This was straight-forward and is
orthogonal to the application code and other tooling.
Reference:
@ -615,9 +604,9 @@ Reference:
### 4.5. Debugging
I've mostly used [Chrome DevTools](https://developer.chrome.com/docs/devtools)
for debugging and the experience was fantastic.
It feels incredibly _immediate_ inspecting an application
without third-party code or any kind of cruft (e.g. source maps).
for debugging and the experience was fantastic. It feels incredibly _immediate_
inspecting an application without third-party code or any kind of cruft (e.g.
source maps).
## 5. Assessment
@ -635,45 +624,45 @@ and usable:
- Local Storage persistence
Additionally, most interactions are smoothly animated at 60 frames per second.
In particular, dragging and dropping gives proper visual feedback
when elements are reordered.
In particular, dragging and dropping gives proper visual feedback when elements
are reordered.
_The latter was an improvement over the original application when I started
working on the case study in 2019. In the meantime, the TeuxDeux
team released an update with a much better drag & drop experience. Great job!_
working on the case study in 2019. In the meantime, the TeuxDeux team released
an update with a much better drag & drop experience. Great job!_
One notable missing feature is Markdown support. It would be unreasonable
to implement Markdown from scratch; this is a valid candidate for using
an external library as it is entirely orthogonal to the remaining codebase.
One notable missing feature is Markdown support. It would be unreasonable to
implement Markdown from scratch; this is a valid candidate for using an external
library as it is entirely orthogonal to the remaining codebase.
The application has been tested on latest Chrome, Firefox, Safari,
and Safari on iOS.
The application has been tested on latest Chrome, Firefox, Safari, and Safari on
iOS.
_TODO Test more browsers and devices._
A fresh load of the original TeuxDeux application transfers around **1.2 MB**
and finishes loading at over **1000 ms**, sometimes up to 2000ms
(measured in 12/2023).
Reloads finish at around **700 ms**.
and finishes loading at over **1000 ms**, sometimes up to 2000ms (measured in
12/2023). Reloads finish at around **700 ms**.
With a transferred size of around **55 KB**, the vanilla application consistently
loads in **300-500 ms**&mdash;not minified and with each script, stylesheet and icon
served as an individual file. Reloads finish at **100-200 ms**; again, not
optimized at all (with e.g. asset hashing/indefinite caching).
With a transferred size of around **55 KB**, the vanilla application
consistently loads in **300-500 ms**&mdash;not minified and with each script,
stylesheet and icon served as an individual file. Reloads finish at **100-200
ms**; again, not optimized at all (with e.g. asset hashing/indefinite caching).
_To be fair, my implementation misses quite a few features from the original. I suspect a fully equivalent clone to be well below 100 KB transfer, though._
_To be fair, my implementation misses quite a few features from the original. I
suspect a fully equivalent clone to be well below 100 KB transfer, though._
_TODO Run more formal performance tests and add figures for the results._
### 5.2. Code Quality
Unfortunately, it is quite hard to find undisputed, objective measurements
for code quality (besides trivialities like code style, linting, etc.).
The only generally accepted assessment seems to be peer reviewal.
Unfortunately, it is quite hard to find undisputed, objective measurements for
code quality (besides trivialities like code style, linting, etc.). The only
generally accepted assessment seems to be peer reviewal.
To have at least some degree of assessment of the code's quality,
the following sections summarize relevant facts about the codebase
and some opinionated statements based on my experience in the industry.
To have at least some degree of assessment of the code's quality, the following
sections summarize relevant facts about the codebase and some opinionated
statements based on my experience in the industry.
#### 5.2.1. The Good
@ -689,7 +678,8 @@ and some opinionated statements based on my experience in the industry.
- State separated from the DOM
- Idempotent updates
- Data flow using custom events
- Compare the proposed architecture to the API/conceptual surface of Angular or React...
- Compare the proposed architecture to the API/conceptual surface of Angular or
React...
- Progressive developer experience
- Markup, style, and behavior are orthogonal and can be developed separately.
- Adding behavior has little impact on the markup besides adding classes.
@ -704,23 +694,24 @@ and some opinionated statements based on my experience in the industry.
All source files (HTML, CSS and JS) combine to **under 3000 lines of code**,
including comments and empty lines.
For comparison, prettifying the original TeuxDeux's minified JS assets
yields **81602 LOC** (12/2023).
For comparison, prettifying the original TeuxDeux's minified JS assets yields
**81602 LOC** (12/2023).
_To be fair, my implementation misses quite a few features from the original. I suspect a fully equivalent clone to be well below 10000 LOC, though._
_To be fair, my implementation misses quite a few features from the original. I
suspect a fully equivalent clone to be well below 10000 LOC, though._
#### 5.2.2. The Verbose
- Stylesheets are a bit verbose. SCSS would help here.
- Simple components require quite some boilerplate code.
- `el.querySelectorAll(':scope ...')` is somewhat default/expected and
would justify a helper.
- `el.querySelectorAll(':scope ...')` is somewhat default/expected and would
justify a helper.
- Listening to and dispatching events is slightly verbose.
- Although not used in this study,
event delegation seems hard to implement without code duplication.
- Although not used in this study, event delegation seems hard to implement
without code duplication.
Eliminating verbosity through build steps and a minimal set of helpers
would reduce the comparably low code size (see above) even further.
Eliminating verbosity through build steps and a minimal set of helpers would
reduce the comparably low code size (see above) even further.
#### 5.2.3. The Bad
@ -728,124 +719,123 @@ would reduce the comparably low code size (see above) even further.
- Event names share a global namespace.
- Especially problematic for events that bubble up.
- No syntax highlighting or code completion in HTML strings.
- Can be mitigated with [es6-string-html](https://marketplace.visualstudio.com/items?itemName=Tobermory.es6-string-html)
- The separation between base HTML and dynamic rendering is not ideal
when compared to JSX, for example.
- Can be mitigated with
[es6-string-html](https://marketplace.visualstudio.com/items?itemName=Tobermory.es6-string-html)
- The separation between base HTML and dynamic rendering is not ideal when
compared to JSX, for example.
- JSX/virtual DOM techniques provide much better development ergonomics.
- Reconciliation is verbose, brittle and repetitive.
I wouldn't recommend the proposed technique
without a well-tested helper function, at least.
- You have to remember mounting behaviors correctly when
creating new elements. It would be helpful to automate this somehow,
e.g. watch elements of selector X (at all times) and ensure the desired
behaviors are mounted once on them.
- No type safety. I've always been a proponent of dynamic languages
but since TypeScript's type system provides the best of both worlds,
I cannot recommend using it enough.
- Reconciliation is verbose, brittle and repetitive. I wouldn't recommend the
proposed technique without a well-tested helper function, at least.
- You have to remember mounting behaviors correctly when creating new elements.
It would be helpful to automate this somehow, e.g. watch elements of selector
X (at all times) and ensure the desired behaviors are mounted once on them.
- No type safety. I've always been a proponent of dynamic languages but since
TypeScript's type system provides the best of both worlds, I cannot recommend
using it enough.
- We're effectively locked out of using NPM dependencies that don't provide
browser-ready builds (ES modules or UMD).
- Most frameworks handle a lot of browser inconsistencies and
continuously monitor regressions with extensive test suites.
The cost of browser testing is possibly higher
when using a vanilla approach.
- Most frameworks handle a lot of browser inconsistencies and continuously
monitor regressions with extensive test suites. The cost of browser testing is
possibly higher when using a vanilla approach.
---
Besides the issues described above, I believe the codebase is well organized
and there are clear paths for bugfixes and feature development.
Since there's no third party code, bugs are easy to find and fix,
and there are no dependency limitations to work around.
Besides the issues described above, I believe the codebase is well organized and
there are clear paths for bugfixes and feature development. Since there's no
third party code, bugs are easy to find and fix, and there are no dependency
limitations to work around.
A certain degree of DOM API knowledge is required but I believe this
should be a goal for any web developer.
A certain degree of DOM API knowledge is required but I believe this should be a
goal for any web developer.
### 5.3. Generality of Patterns
Assessing the generality of the discovered techniques objectively is
not really possible without production usage. From my experience, however,
I can't imagine any scenario where mount functions, event-based data flow etc.
are not applicable. The underlying principles power the established frameworks,
after all:
Assessing the generality of the discovered techniques objectively is not really
possible without production usage. From my experience, however, I can't imagine
any scenario where mount functions, event-based data flow etc. are not
applicable. The underlying principles power the established frameworks, after
all:
- State is separated from the DOM (React, Angular, Vue).
- Rendering is idempotent and complete (React's pure `render` function).
- One-way data flow (React)
An open question is if these patterns hold for library authors.
Although not considered during the study, some observations can be made:
An open question is if these patterns hold for library authors. Although not
considered during the study, some observations can be made:
- The JavaScript itself would be fine to share as ES modules.
- Event naming needs great care, as dispatching (bubbling) events
from imported behaviors can trigger parent listeners in consumer code.
- Event naming needs great care, as dispatching (bubbling) events from imported
behaviors can trigger parent listeners in consumer code.
- Can be mitigated by providing options to prefix or map event names.
- CSS names share a global namespace and need to be managed as well.
- Can also be mitigated by prefixing, however making the JavaScript
a bit more complex.
- Can also be mitigated by prefixing, however making the JavaScript a bit more
complex.
## 6. Conclusion
The result of this study is a working to-do application with decent UI/UX and
most of the functionality of the original TeuxDeux app,
built using only standard web technologies.
It comes with better overall performance
at a fraction of the code size and bandwidth.
most of the functionality of the original TeuxDeux app, built using only
standard web technologies. It comes with better overall performance at a
fraction of the code size and bandwidth.
The codebase seems manageable through a handful of simple concepts,
although it is quite verbose and even messy in some areas.
This could be mitigated by a small number of helper functions and
simple build steps (e.g. SCSS and TypeScript).
The codebase seems manageable through a handful of simple concepts, although it
is quite verbose and even messy in some areas. This could be mitigated by a
small number of helper functions and simple build steps (e.g. SCSS and
TypeScript).
The study's method helped discovering patterns and techniques that
are at least on par with a framework-based approach for the given subject,
without accidentally building a custom framework.
The study's method helped discovering patterns and techniques that are at least
on par with a framework-based approach for the given subject, without
accidentally building a custom framework.
A notable exception to the latter is rendering variable numbers of elements
in a concise way. I was unable to eliminate the verbosity involved
in basic but efficient reconciliation.
Further research is needed in this area, but for now this appears to be
a valid candidate for a (possibly external) general-purpose utility.
A notable exception to the latter is rendering variable numbers of elements in a
concise way. I was unable to eliminate the verbosity involved in basic but
efficient reconciliation. Further research is needed in this area, but for now
this appears to be a valid candidate for a (possibly external) general-purpose
utility.
When looking at the downsides, remember that all of the individual parts are
self-contained, highly decoupled, portable, and congruent to the web platform.
The implementation cannot "rust", by definition, as no dependencies
can become out of date.
The implementation cannot "rust", by definition, as no dependencies can become
out of date.
Another thought to be taken with a grain of salt: I believe frameworks
make simple tasks even simpler, but hard tasks (e.g. implementing cross-cutting
Another thought to be taken with a grain of salt: I believe frameworks make
simple tasks even simpler, but hard tasks (e.g. implementing cross-cutting
concerns or performance optimizations) often more difficult.
---
Setting some constraints up-front forced me to challenge
my assumptions and preconceptions about vanilla web development.
It was quite liberating to avoid general-purpose utilities and
get things done with what's readily available.
Setting some constraints up-front forced me to challenge my assumptions and
preconceptions about vanilla web development. It was quite liberating to avoid
general-purpose utilities and get things done with what's readily available.
While I think the study is relatively complete, there's always more to explore.
[Ideas, questions, bug reports](https://github.com/morris/vanilla-todo/issues) and
pull requests are more than welcome!
[Ideas, questions, bug reports](https://github.com/morris/vanilla-todo/issues)
and pull requests are more than welcome!
Finally, this case study does not question using dependencies, libraries or frameworks
in general&mdash;code sharing is an essential part of software engineering.
It was a constrained experiment designed to discover novel methods
for vanilla web development and, hopefully,
inspire innovation and further research in the area.
Finally, this case study does not question using dependencies, libraries or
frameworks in general&mdash;code sharing is an essential part of software
engineering. It was a constrained experiment designed to discover novel methods
for vanilla web development and, hopefully, inspire innovation and further
research in the area.
## 7. Beyond Vanilla
As detailed in the assessment, the result of the case study
could be significantly improved if build steps and helpers were allowed.
Beyond the strict rules I've used in this experiment,
here are a few ideas I'd like to see explored in the future:
As detailed in the assessment, the result of the case study could be
significantly improved if build steps and helpers were allowed. Beyond the
strict rules I've used in this experiment, here are a few ideas I'd like to see
explored in the future:
- Run another case study with TypeScript, SCSS, and build steps (seems promising).
- Extrapolate deep utility functions (e.g. `reconcile()`) to mitigate some of the discovered downsides.
- Experiment with architectures based on virtual DOM rendering and standard DOM events.
- Run another case study with TypeScript, SCSS, and build steps (seems
promising).
- Extrapolate deep utility functions (e.g. `reconcile()`) to mitigate some of
the discovered downsides.
- Experiment with architectures based on virtual DOM rendering and standard DOM
events.
- Compile discovered rules, patterns and techniques into a comprehensive guide.
Case studies constrained by a set of formal rules are an effective way to find
new patterns and techniques in a wide range of domains.
I'd love to see similar experiments in the future.
new patterns and techniques in a wide range of domains. I'd love to see similar
experiments in the future.
## 8. Appendix
@ -903,7 +893,8 @@ Thanks!
- Added [tooling section](#4-tooling)
- Refactored business logic into pure functional module
- Added support for [code coverage](#431-code-coverage)
- Added [local development server](#41-local-development-server) with hot reloading
- Added [local development server](#41-local-development-server) with hot
reloading
- Fixed some visual issues
- Updated dependencies
@ -932,13 +923,13 @@ Thanks!
### 10/2020
- Refactored for `dataset` [#2](https://github.com/morris/vanilla-todo/issues/2) &mdash;
[@opethrocks](https://github.com/opethrocks)
- Fixed [#3](https://github.com/morris/vanilla-todo/issues/3) (navigation bug) &mdash;
[@anchepiece](https://github.com/anchepiece),
- Refactored for `dataset` [#2](https://github.com/morris/vanilla-todo/issues/2)
&mdash; [@opethrocks](https://github.com/opethrocks)
- Fixed [#3](https://github.com/morris/vanilla-todo/issues/3) (navigation bug)
&mdash; [@anchepiece](https://github.com/anchepiece),
[@jcoussard](https://github.com/jcoussard)
- Fixed [#4](https://github.com/morris/vanilla-todo/issues/4) (double item creation) &mdash;
[@n0nick](https://github.com/n0nick)
- Fixed [#1](https://github.com/morris/vanilla-todo/issues/4) (bad links) &mdash;
[@roryokane](https://github.com/roryokane)
- Fixed [#4](https://github.com/morris/vanilla-todo/issues/4) (double item
creation) &mdash; [@n0nick](https://github.com/n0nick)
- Fixed [#1](https://github.com/morris/vanilla-todo/issues/4) (bad links)
&mdash; [@roryokane](https://github.com/roryokane)
- Initial version