Old cheat on separate repo: web.
Now moving to either:
- separate files under: web-cheat/ for the boring stuff
- subsections under this section for the more exciting stuff!
Examples under:
This is my stack. There are many like it, but this one is mine.My stack is my best friend. It is my life. I must master it as I must master my life.Without me, my stack is useless. Without my stack, I am useless. I must fire my requests true. I must shoot straighter than my hackers who are trying to kill me. I must shoot him before he shoots me. I will ...My stack is human, even as I am human, because it is my life. Thus, I will learn it as a brother. I will learn its weaknesses, its strength, its parts, its accessories, its ORMs and its asset bundlers. I will keep my stack clean and ready, even as I am clean and ready. We will become part of each other. We will ...Before God, I swear this creed. My stack and I are the defenders of my website. We are the masters of our enemy. We are the saviors of my life.So be it, until victory is mine and there is no enemy, but peace!
Explanation: this is an allusion to the Rifleman's Creed. This particular version talks about the website stack chosen for a website, i.e. the libraries used.
Ciro Santilli has always felt that choosing a stack is an almost religious choice. It is perhaps part of why the prayer style of the original Rifleman's Creed resonates with the web stack choice.
It is very hard to know how things are going go, the ups and downs, before putting big hours into it.
And once you start, it is hard, though not impossible, to move away.
The same allusion would make sense with any complex library choice, but it is particularly apparent in web development since there are so many different web stacks to choose from. A bit like rifles, they are all somewhat fungible, though of course not as much.
Examples:
- html/min.html: minimal valid HTML document. It is insane however.
- html/min-sane.html: minimal sane HTML document. There are smaller valid ones, but they are insane.
- html/img.html
- html/img-broken.html: stackoverflow.com/questions/22051573/how-to-hide-image-broken-icon-using-only-css-html
- html/img-load-lazy.html: stackoverflow.com/questions/2321907/how-do-you-make-images-load-lazily-only-when-they-are-in-the-viewport/57389607#57389607
- html/iframe.html. Uses: html/iframe2.html, html/hello.txt and html/hello
- forms
- YouTube embeds
Allows us to draw with JavaScript pixel by pixel! Great way to create computational physics demos!
Here is an animation demo with some useful controls:
HTML snippet:
new class extends OurbigbookCanvasDemo {
init() {
super.init('hello');
this.pixel_size_input = this.addInputAfterEnable(
'Pixel size',
{
'min': 1,
'type': 'number',
'value': 1,
}
);
}
draw() {
var pixel_size = parseInt(this.pixel_size_input.value);
for (var x = 0; x < this.width; x += pixel_size) {
for (var y = 0; y < this.height; y += pixel_size) {
var b = ((1.0 + Math.sin(this.time * Math.PI / 16)) / 2.0);
this.ctx.fillStyle =
'rgba(' +
(x / this.width) * 255 + ',' +
(y / this.height) * 255 + ',' +
b * 255 +
',255)'
;
this.ctx.fillRect(x, y, pixel_size, pixel_size);
}
}
}
}
HTML snippet:
new class extends OurbigbookCanvasDemo {
init() {
super.init('webgl', {context_type: 'webgl'});
this.ctx.viewport(0, 0, this.ctx.drawingBufferWidth, this.ctx.drawingBufferHeight);
this.ctx.clearColor(0.0, 0.0, 0.0, 1.0);
this.vertexShaderSource = `
#version 100
precision highp float;
attribute float position;
void main() {
gl_Position = vec4(position, 0.0, 0.0, 1.0);
gl_PointSize = 64.0;
}
`;
this.fragmentShaderSource = `
#version 100
precision mediump float;
void main() {
gl_FragColor = vec4(0.18, 0.0, 0.34, 1.0);
}
`;
this.vertexShader = this.ctx.createShader(this.ctx.VERTEX_SHADER);
this.ctx.shaderSource(this.vertexShader, this.vertexShaderSource);
this.ctx.compileShader(this.vertexShader);
this.fragmentShader = this.ctx.createShader(this.ctx.FRAGMENT_SHADER);
this.ctx.shaderSource(this.fragmentShader, this.fragmentShaderSource);
this.ctx.compileShader(this.fragmentShader);
this.program = this.ctx.createProgram();
this.ctx.attachShader(this.program, this.vertexShader);
this.ctx.attachShader(this.program, this.fragmentShader);
this.ctx.linkProgram(this.program);
this.ctx.detachShader(this.program, this.vertexShader);
this.ctx.detachShader(this.program, this.fragmentShader);
this.ctx.deleteShader(this.vertexShader);
this.ctx.deleteShader(this.fragmentShader);
if (!this.ctx.getProgramParameter(this.program, this.ctx.LINK_STATUS)) {
console.log('error ' + this.ctx.getProgramInfoLog(this.program));
return;
}
this.ctx.enableVertexAttribArray(0);
var buffer = this.ctx.createBuffer();
this.ctx.bindBuffer(this.ctx.ARRAY_BUFFER, buffer);
this.ctx.vertexAttribPointer(0, 1, this.ctx.FLOAT, false, 0, 0);
this.ctx.useProgram(this.program);
}
draw() {
this.ctx.clear(this.ctx.COLOR_BUFFER_BIT);
this.ctx.bufferData(this.ctx.ARRAY_BUFFER, new Float32Array([Math.sin(this.time / 60.0)]), this.ctx.STATIC_DRAW);
this.ctx.drawArrays(this.ctx.POINTS, 0, 1);
}
}
- css/code-block.html
- css/img-table-vertical-center.html
- css/viewport-height.html: a div that is a tall as the viewport, and does not generate a toplevel scrollbar
- css/responsive-image-max-height.html: here we try to create an image that is never wider than the screen. If the screen is less wide than the image, then the image scales down proportionally. Otherwise, the image has a user determined fixed by the CSS or the HTML
height
property. Related:TODO I'm unable to do this....... stackoverflow.com/questions/69964332/how-to-set-the-default-height-of-responsive-images-when-screen-is-wide-and-have The objective was to implement: github.com/ourbigbook/ourbigbook/issues/168 - css/top-navigation.html
- css/flex.html: illustrates basic flex usage, including:
flex-grow
: if there's space left, this determines how much extra space will be given to each.flex-basis
: the size the items want to be. But if there isnt' enough space, this can be cut up.Note that the minimal space required by children of the flex children cannot be necessarily cut up, and might lead things to overflow out of the container.flex-shrink
: if there's space missing, this determines how much extra space will be removed from eachflex-basis
Other examples include:
- css/flex-fill-vertical.html: minimal setup for a editor: docs.ourbigbook.com/editor
That example calculates and displays the final widths via JavaScript, making it easier to understand the calculations being done.
The more of their syntax gets merged into mainline Cascading Style Sheets, the better the world will be.
- js/confirm-close.html: stackoverflow.com/questions/7317273/warn-user-before-leaving-web-page-with-unsaved-changes
- web-cheat/js-image-load.html: load an image from JavaScript dynamically: stackoverflow.com/questions/226847/what-is-the-best-javascript-code-to-create-an-img-element
- web-cheat/js-image-load-viewport.html: load an image from JavaScript dynamically when it would become visible on the viewport: stackoverflow.com/questions/2321907/how-do-you-make-images-load-only-when-they-are-in-the-viewport
- html/img-load-lazy.html: stackoverflow.com/questions/2321907/how-do-you-make-images-load-lazily-only-when-they-are-in-the-viewport/57389607#57389607
- web-cheat/esm.html: ESM modules
- js/keydown.html: stackoverflow.com/questions/16006583/capturing-ctrlz-key-combination-in-javascript
External libraries
- Text editors
- Interactive HTML table sorting
In order to make websites efficient and portable, a lot of transpilation is needed.
Webpack is like a magic hydra that can eat any type of file and bundle it into a single output: .js, .ts, .ccs, .scss, .jsx, .tsx,
require
, import
, import
css from .js
, it doesn't matter at all, it just digests all into the same dump.When it works, you are just left in awe. When it doesn't, you're fucked and have to debug for several hours.
Demos under: webpack/.
webpack/template contains a reasonable starter template.
Usage:
cd webpack/template
npm install
npm run build
This will produce, under
dist/
the following minimized files:dist/index.html
: from webpack/template/index.html. You can open it to see:show on the browser. This was added from JavaScript.Hello webpack
dist/index.js
: from webpack/template/index.js and anything in its import tree, e.g.:- webpack/template/main.scss: sass source. It gets embedded the the JavaScript output as a string, and the JavaScript then applies it to the page, making the font blue
lodash
third party library
You can also run this test with the development server on localhost:9000:
which uses unminimized outptus, and automatically push reloads the page whenever you change any of the input files!
npm start
This example shows how to use Webpack/sass.
To make things simple, it generates a completely separate
dist/index.js
and dist/main.css
which are manually included from index.html
, and does not do any type of injection (neither Js into HTML nor CSS in Js).This example shows how you could manually include the
dist/index.js
that is output from webpack into your index.html
.This is generally not what you want to do, because what you actually want to do is to use a Js output name with a hash in it, so that browsers only need to refetch when the name changes.
And to do that, we have to let webpack dynamically inject that unpredictable hash as done in webpack/template with:
new HtmlWebpackPlugin({
filename: 'index.html',
// Inject the include to our hashed filename,
// since it is not deterministic due to the hash.
inject: true,
template: path.resolve(__dirname, 'index.html'),
}),
This shows how to produce a minimized fully embedded CSS file with webpack from a sass:
That example produces a
cd webpack/sass
npm install
npm run build
xdg-open index.html
dist/main.css
file which is a compresesd combination of:- webpack/sass/main.scss
- normalize.css, added to the project as a regular
node_modules
package
Google is trying to kill it as of 2021: www.omgubuntu.co.uk/2021/01/chromium-sync-google-api-removed The lack of sync is a major major blow. So selfish. Google makes billions, and it won't give in a little bit of settings storage...
Lol it is note possible what a joke. Notably this makes it harder to have of a superior third party password manager like Proton Pass (though there seems to be an autocomplete app as an alternative path), and an ad blocker. Fuck Google.
Also, Chromium is not available on Google Play by default, you can install the apk, but you will miss updates:
How to select one:
A (multi-user) blog is the hello world of the web, so creating one of those is the best way to quickly evaluate web technology, i.e. time to Hello World.
Some new frameworks like FeathersJS are making a chat app instead, as that highlights the push notifications a bit better.
Ciro Santilli's implementation: node Express Sequelize Next.js realworld example app.
Ahh, you can't have new ideas anymore!
Basically puts together every backend with Front-end web framework to create the exact same website.
The reference live demo can be found at: demo.realworld.io/#/ It is based on Angular.js as it links to: github.com/gothinkster/angularjs-realworld-example-app TODO backend?
There are however also live demos of other frontends, e.g.:Note that all those frontends communicate with the same backend.
- React: react-redux.realworld.io. But note that tag addition at post creation is broken there as of March 2021, but not on master: github.com/gothinkster/react-redux-realworld-example-app/issues/151#issuecomment-808417846 so they forgot to update the live server.
- Vue.js: vue-vuex-realworld.netlify.app
As of 2021 Devs are seemed a bit too focused on monetizing the project through their "how to use this project" premium tutorial, and documentation could be better: just getting the hello world of the most popular backend with the most popular frontend is not easy... come on.
github.com/gothinkster/realworld/issues/578 asks for community support, as devs have moved on since unfortunately.
Remember:
- by default, the frontends hardcode the upstream public data API:
https://conduit.productionready.io/api
so you have to hack their code to match the port of the backend. And each backend can have a different port. - when you switch between backends, you must first manually clear client-side storage cookies/local new run will fail due to authentication issues!
Important missing things from the minimum base app:
- server-side rendering:
- github.com/arrlancore/nextjs-ssr-real-world-app-example. As advertised, that global instance does render with JavaScript disabled! Proposed for upstream at: github.com/gothinkster/realworld/issues/423
- github.com/gothinkster/realworld/issues/266
- no javaScript bi-directional communication library built-in... come on: github.com/gothinkster/realworld/issues/107
- email notifications however as tested on the live demo: demo.realworld.io/#/
- error handling is broken/missing/inconsistent across apps
First you should the most popular backend/frontend combination running, which is the most likely to be working. We managed to run on Ubuntu 20.10, React + Node.js Express.js as described at github.com/gothinkster/node-express-realworld-example-app/pull/116:Then just:
on both server and client, and then visit the client URL: localhost:4100/
- github.com/cirosantilli/node-express-realworld-example-app/tree/mongo4 which has a simple patch on top of github.com/gothinkster/node-express-realworld-example-app/tree/ba04b70c31af81ca7935096740a6e083563b3a4a for MongoDB 4 supportThis requires you to first install MongoDB on Ubuntu and ensure you can login to it from the command line.
- github.com/gothinkster/react-redux-realworld-example-app/tree/9186292054dc37567e707602a15a0884d6bdae35 patched to use the correct server host/port
localhost:3000
:diff --git a/src/agent.js b/src/agent.js index adfbd72..e3cdc7f 100644 --- a/src/agent.js +++ b/src/agent.js @@ -3,7 +3,7 @@ import _superagent from 'superagent'; const superagent = superagentPromise(_superagent, global.Promise); -const API_ROOT = 'https://conduit.productionready.io/api'; +const API_ROOT = 'http://localhost:3030/api'; const encode = encodeURIComponent; const responseBody = res => res.body;
npm install
npm start
You have to hit the Enter key to add tags, it's terrible: github.com/gothinkster/react-redux-realworld-example-app/issues/151#issuecomment-808417846
One cool thing is that the main repo has unified backend API tests:
so the per-repository tests are basically useless, and that single test can test everything for any backend! There is no frontend testing however: github.com/gothinkster/realworld/issues/269 so newb.
git clone https://github.com/gothinkster/realworld
cd realworld
git checkout e7adc6b06b459e578d7d4a6738c1c050598ba431
cd api
APIURL=http://localhost:3000/api USERNAME="u$(date +%s)" ./run-api-tests.sh
Setups we've tried:
- backend:
- randyscotsmithey/feathers-realworld-example-app worked with React and Vue.js
- the React setup failed as shown at: github.com/gothinkster/react-redux-realworld-example-app/issues/187
- gothinkster/django-realworld-example-app
- the Nest.js failed on Ubuntu 20.10 as per github.com/lujakob/nestjs-realworld-example-app/issues/19
- frontend:
Front-end only, so infinitely simpler, and generally much less useful than gothinkster/realworld.
You need those because it is hard to do the following:
- client JavaScript sends a request to server
- server sends back data
- client updates what the user sees
This is hard to do notably because when the update happens, several things might need to change on the webpage at the same time.
Notably, new elements might need to be added to the webpage, which in turn means that new bindings such as button clicks have to be added to those, in a way that keeps the page working.
The only way to do this basically is to have a functional dependency graph that keeps everything in the page in working state as updates come.
Website: reactjs.org
React officially recommends that you use Next.js[ref], so just do it. It just sets up obvious missing functionality from raw React.
React feels like a good. But it also feels impossible to use/learn sometimes.
Its main design goal is to reduce DOM changes to improve rendering times.
And an important side effect of that is that it becomes easier to do stuff of the type:and then the new comment easily gets the callback attached to it.
- user creates a new comment that appears on screen without page reload
- comment has a delete button, which is JavaScript callback activated
And it also ends up naturally doubling as a template engine.
But React can also be extremelly hard to use. It can be very hard to know what you can and cannot do sometimes, then you have to stop and try to understand how react works things better:The biggest problem is that it is hard to automatically detect such errors, but perhaps this is the same for other frontend stuff. Though when doing server-side rendering, the setup should really tell you about such errors, so you don't just discover them in production later on.
- cannot update a component while rendering a different component warning in React
- Rendered more hooks than during the previous render.
- cannot use hooks from helpers:
Is is also very difficult to understand precisely why hooks run a certain number of times.
Examples under: web-cheat/react.
- web-cheat/react/hello.html: minimal example. As you click:By opening a web inspector, you can see that only modified elements get updated. So we understand that JSX parses its "HTML-like" into a tree, and then propagates updates on that tree.
- one counter increments every time
- the other increments every two clicks
By looking at the terminal, we see thatrender()
does get called every time the button is clicked, so the tree gets recreated every time. - web-cheat/react/hello-hook.html: Hello World with hooks instead of classes, but also that is fully correct and optimized. Exactly equivalent to web-cheat/react/hello.html.
React.useState
plays the role of the constructor.Hooks were introduced much after classes, and just require less code, so everyone is using them now instead of classes.It appears that the hello world in the React.js docs is wrong though, you need functional sets to update values based on their current value: stackoverflow.com/questions/375913/how-can-i-profile-c-code-running-on-linux/60265409#60265409, otherwise you could lose updates. ThesetTimeout
example from stackoverflow.com/questions/57828368/why-react-usestate-with-functional-update-form-is-needed/65306828#65306828 is particularly relevant. A real world case would be that but waiting for network requests to update.We cannot reproduce a quick double click faliure without the functional update however, not even withe = document.getElementById('button');e.click();e.click()
. - web-cheat/react/hello-without-jsx.html: Hello World in pure JavaScript, without JSX. Exactly equivalent to web-cheat/react/hello.html. Documented at: reactjs.org/docs/react-without-jsx.html Understanding this is fundamental to understanding React.
- web-cheat/react/prop-change.html: shows what gets called as parameters flow down through the tree.By looking at the console, we see all
render
get called every time, even ifprops
didn't change, but not the constructors.After page load the console contains:Main.constructor Main.render NotMain.constructor NotMain.render NotMain2.constructor NotMain2.render
Then, every time we click the button it adds:handleClick Main.render NotMain.render NotMain2.render
Note how theprops
ofNotMain
only change every other click, butrender
still gets called every time.In order to makeReact
not re-render when there are not changes, you have to either:- define the
shouldComponentUpdate
method of class components - wrap functional components in
React.memo
- define the
- web-cheat/react/prop-change-hook.html: same as web-cheat/react/prop-change.html, but using hooks. The notable difference is that functional components don't have a clear constructor/render separation, the function just gets called every time. Then React does some magic to ensure that
useState
returns the current state, except for the first render where they return the initial value. - web-cheat/react/prop-change-hook-use-memo.html: TODO forgot if this example is useful, was tring to use
useMemo
- web-cheat/react/prop-change-child.html: shows what child prop changes do not call render on parent,
Main
does not show up on console when you click underNotMain
- web-cheat/react/hook-from-function-fail.html: TODO got some errors that seemed linked to this on a larger program, but failed to minimize them here
- web-cheat/react/hook-different-number-of-times.html: this illustrates one of the cardinal points of using hooks: you must always call them the same number of times, otherwise it fails with:
React has detected a change in the order of Hooks called by Main. This will lead to bugs and errors if not fixed.
In the case ofuseState
, we can kind of understand why this happens: React must use the order of calls to determine which state variable to return at each point in time. - web-cheat/react/hello-hook-use-effect.html: just checking when it gets called. Happens after every render
handleClick Main useEffect useEffect2
- TODO create a test
\a[web-cheat/react/img-broken.html]
How React works bibliography:
- www.netlify.com/blog/2019/03/11/deep-dive-how-do-react-hooks-really-work/ shows how
uesState
works under the hood with crazy closures - medium.com/@gethylgeorge/how-virtual-dom-and-diffing-works-in-react-6fc805f9f84e
Minimal reproduction: stackoverflow.com/questions/62336340/cannot-update-a-component-while-rendering-a-different-component-warning/70317831#70317831
Framework built on top of React.
Officially recommended by React[ref]:
Recommended ToolchainsIf you’re building a server-rendered website with Node.js, try Next.js.
gothinkster/realworld blog example by Ciro Santilli: node Express Sequelize Next.js realworld example app.
Basically what this does is to get server-side rendering just working by React, including hydration, which is a good thing.
Next.js sends the first pre-rendered HTML page along with the JavaScript code. Then, JavaScript page switches just load the API data.
Next.js does this nicely by forcing you to provide page data in a serialized JSON format, even when rendering server-side (e.g. the return value of
getServerSideProps
). This way, it is also able to provide either the full HTML, or just the JSON.Some general downsides:
- it does feel like they don't document deployment very well however, especially non-Vercel options, which is the company behind Next.js. I'm unable to find how to use a non Vercel CDN with ISR supposing that is possible.
- Next.js is very opinionated, and like any opinionated library it is sometimes hard to know why something is/isn't happening, and sometimes it is hard/impossible to do what you want with it unless they add support. They have done good progress, but even as of 2022, some aspects just feel so immature, some major-looking use cases are not very well done.
In theory, Next.js could be the "ultimate frontend framework". It does have a lot of development difficulties that need to be ironed out, but the general concepts, and things it tries to integrate, including e.g. webpack, TypeScript, etc. are good. Maybe the question is when will someone put it together with an amazing backend library and dominate and finally put an end to the infinite number of Js Frameworks!
In-tree examples at: github.com/vercel/next.js/tree/canary/examples
In order to offer its amazing features, Next.js is also extremely opinionated, which means that if something wasn't designed to be possible, it basically isn't.
No prerender with custom server? It forces you to write your API with next as well? Or does it mean something else?
TODO can it statically generate pages that are created at runtime? E.g. if I create a new blog post, will it automatically upload a static page? It seems that yes, and that this is exactly what Incremental Static Regeneration means:However, Ciro can't find any mention of how to specify where the pages are uploaded to... this is pat of the non-Vercel deployment problem.
- github.com/vercel/next.js/discussions/25410
- vercel.com/docs/next.js/incremental-static-regeneration
- github.com/vercel/next.js/discussions/17711
- www.reddit.com/r/nextjs/comments/mvvhym/a_complete_guide_to_incremental_static/
- github.com/vercel/next.js/discussions/11552#discussioncomment-115595
- stackoverflow.com/questions/62105756/how-to-use-aws-with-next-js
- github.com/vercel/next.js/discussions/17080
- github.com/vercel/next.js/discussions/16852
Can't ISR prerenter by URL query parameters:
That plus the requirement to have one page per file under
pages/
leads to a lot of useless duplication, because then you are forced to place the URL parameters on the pathnames."Module not found: Can't resolve 'fs'" Hell. The main reason this happens seems to be the that in a higher order component, webpack can't determine if callbacks use the require or not to remove it from frontend code. Fully investigated and solved at:
Overviews:
- www.reddit.com/r/reactjs/comments/8evy5d/what_are_the_downsides_to_nextjs/ 2017 What are the downsides to Next.js?
TODO answer:
Our oxamples under nodejs/next:
- nodejs/next/hello-world: a hello world. There's an in-tree one at: github.com/vercel/next.js/tree/e75361fd03872b097e817634c049b3185f24cf56/examples/hello-world, but ours is truly minimal
- nodejs/next/hoc: shows how to use a higher order component (HOC) to factor out
getStaticProps
across two pages: nodejs/next/hoc/pages/index.js and nodejs/next/hoc/pages/notindex.js - nodejs/next/typescript: simple TypeScript example, minimized from: github.com/vercel/next.js/tree/d61b0761efae09bd9cb1201ff134ed8950d9deca/examples/with-typescriptNotably, that shows how
require
errors are avoided in that case as mentioned at: stackoverflow.com/questions/64926174/module-not-found-cant-resolve-fs-in-next-js-application/70363153#70363153 - nodejs/next/localStorage: a counter that is persistent across page reloads by using
localStorage
. Used in: stackoverflow.com/questions/54819721/next-js-access-localstorage-before-rendering-page/68136224#68136224
Solved ones:
- solved by preview mode in Next.js 12:
- ISR was basically unusable for CRUD websites because you can't force a one-off immediate page update: