Paint for Kids

https://paint.v-collaborate.com

Paint for Kids is a free paint app, with no ads and no tracking code. No cookies or whatsoever are used to track you or the usage of the app. No data about users or devices are collected. I only count the number of downloads. It can be installed on most devices, by just adding it to the home screen. The app works offline.

Main goal of this app is having fun with painting. Even little kids should have no problems using it and parents should not have any privacy concerns letting them.

Use a touch screen compatible pen for the best user experience.

If you have any issues with the app or want to see new features, just create an github issue please.

Setup

Install dependencies:

npm i

Build

This sample uses esbuild as compiler to transpile to JavaScript.

To build the JavaScript version of your component:

npm run bundle

To run the bundle (before create certificates).

npm run serve:bundle

To watch files and rebuild when the files are modified, run the following command:

npm run serve

Both the TypeScript compiler and lit-analyzer are configured to be very strict. You may want to change tsconfig.json to make them less strict.

Testing

This sample uses jest and the open-wc test helpers for testing. See the open-wc testing documentation for more information.

Tests can be run with the test script:

npm run test

Dev Server

This sample uses open-wc's web-dev-server for previewing the project without additional build steps. ES dev server handles resolving Node-style "bare" import specifiers, which aren't supported in browsers. It also automatically transpiles JavaScript and adds polyfills to support older browsers.

Test service worker

First create once the certificates. Best tool for that is mkcert (see https://blog.filippo.io/mkcert-valid-https-certificates-for-localhost/).

For example:

mkcert -install
mkcert -cert-file certs/cert.pem -key-file certs/key.pem v-collaborate.com '*.v-collaborate.com' localhost 127.0.0.1 ::1

Configure the certificates in the file web-dev-server.build.mjs.

To test, that the serviceworker, something has to change in the shipped code. E.g. the buildid.

So run the server as follows:

BUILDID=1 npm run serve:bundle

Open the browser. Go to the about page.

Stop the server and restart it with a different buildid.

BUILDID=2 npm run serve:bundle

Reload the browser. The same version as before should be shown and a box should appear hinting you, that a new version is available. Click on the refresh button and the new bundleid should appear.

Build Docker image

npm run bundle && docker build -t waxolunist/paint2:latest -t waxolunist/paint2:latest .
docker save waxolunist/paint2:latest | gzip > paint_latest.tar.gz

Or tag and push

 docker login registry.v-collaborate.com
 npm run bundle && docker build -t waxolunist/paint2:latest .
 docker tag waxolunist/paint2:latest registry.v-collaborate.com/dev/waxolunist/paint2:latest
 docker push registry.v-collaborate.com/dev/waxolunist/paint2:latest

Run it with:

docker rm paintforkids
docker run -p 8043:8043 --name paintforkids waxolunist/paint2:latest

Editing

If you use VS Code, we highly reccomend the lit-plugin extension, which enables some extremely useful features for lit-html templates:

Syntax highlighting
Type-checking
Code completion
Hover-over docs
Jump to definition
Linting
Quick Fixes

The project is setup to reccomend lit-plugin to VS Code users if they don't already have it installed.

Linting

Linting of TypeScript files is provided by ESLint and TypeScript ESLint. In addition, lit-analyzer is used to type-check and lint lit-html templates with the same engine and rules as lit-plugin.

The rules are mostly the recommended rules from each project, but some have been turned off to make LitElement usage easier. The recommended rules are pretty strict, so you may want to relax them by editing .eslintrc.json and tsconfig.json.

To lint the project run:

npm run lint

Formatting

Prettier is used for code formatting. It has been pre-configured according to the Polymer Project's style. You can change this in .prettierrc.json.

Prettier has not been configured to run when commiting files, but this can be added with Husky and and pretty-quick. See the prettier.io site for instructions.

More information

See Get started on the LitElement site for more information.

TWA

see TWA

When jdk8 is installed correctly, install android tools by executing

scripts/install_adb_cli.sh mac

Alternatively you can also install "win" or "linux" versions. Default is "linux".

Then configure bubblewrap. I prepared the script

scripts/config_bubblewrap.sh

After that start by building

npm run twa:build

Build systems

Not one build system is perfect. Each has its issues.

Using rollup, the webworker loader could not run in watch mode, thus resulting in slow development cycles.
Esbuild is a better alternative, blazing fast btw, but workers are hard to get right when bundling
Testing with ts-jest has problems with workers
esbuild has problems with debugging and dynamic imports

Issues

Dev

Server

Server fallback page
Store file on server (share url)?
Better gzipping (brtl) - change to nginx
reload on about page not working
build and push docker image in dev azure
include a robots.txt

Bugs

console.error on back navigation - can't find blob url

Waxolunist/paint2