fix(generator): more cleanup to plugin framework (apache#18027)

* fix(generator): more cleanup to plugin framework

* fix typo and package name

* add docs

* fix typo

* Update superset-frontend/webpack.config.js

Co-authored-by: Kamil Gabryjelski <kamil.gabryjelski@gmail.com>

* fix generator reference

* add steps to tutorial and fix package version

* refine docs/readme

Co-authored-by: Kamil Gabryjelski <kamil.gabryjelski@gmail.com>

docs/src/pages/docs/Contributing/creating-viz-plugins.mdx

@@ -0,0 +1,137 @@
+---
+name: Creating Visualization Plugins
+menu: Contributing
+route: /docs/contributing/creating-viz
+index: 9
+version: 1
+---
+
+## Creating Visualization Plugins
+
+Visualizations in Superset are implemented in JavaScript or TypeScript. Superset
+comes preinstalled with several visualizations types (hereafter "viz plugins") that
+can be found under the `superset-frontend/plugins` directory. Viz plugins are added to
+the application in the `superset-frontend/src/visualizations/presets/MainPreset.js`.
+The Superset project is always happy to review proposals for new high quality viz
+plugins. However, for highly custom viz types it is recommended to maintain a fork
+of Superset, and add the custom built viz plugins by hand.
+
+### Prerequisites
+
+In order to create a new viz plugin, you need the following:
+
+- Run MacOS or Linux (Windows is not officially supported, but may work)
+- Node.js 16
+- npm 7 or 8
+
+A general familiarity with [React](https://reactjs.org/) and the npm/Node system is
+also recommended.
+
+### Creating a simple Hello World viz plugin
+
+To get started, you need the Superset Yeoman Generator. It is recommended to use the
+version of the template that ships with the version of Superset you are using. This
+can be installed by doing the following:
+
+```bash
+npm i -g yo
+cd superset-frontend/packages/generator-superset
+npm i
+npm link
+```
+
+After this you can proceed to create your viz plugin. Create a new directory for your
+viz plugin with the prefix `superset-plugin-chart` and run the Yeoman generator:
+
+```bash
+mkdir /tmp/superset-plugin-chart-hello-world
+cd /tmp/superset-plugin-chart-hello-world
+```
+
+Initialize the viz plugin:
+
+```bash
+yo @superset-ui/superset
+```
+
+After that the generator will ask a few questions (the defaults should be fine):
+
+```
+$ yo @superset-ui/superset
+
+     _-----_     ╭──────────────────────────╮
+    |       |    │      Welcome to the      │
+    |--(o)--|    │    generator-superset    │
+   `---------´   │        generator!        │
+    ( _´U`_ )    ╰──────────────────────────╯
+    /___A___\   /
+     |  ~  |
+   __'.___.'__
+ ´   `  |° ´ Y `
+
+? Package name: superset-plugin-chart-hello-world
+? Description: Hello World
+? What type of chart would you like? Time-series chart
+   create package.json
+   create .gitignore
+   create babel.config.js
+   create jest.config.js
+   create README.md
+   create tsconfig.json
+   create src/index.ts
+   create src/plugin/buildQuery.ts
+   create src/plugin/controlPanel.ts
+   create src/plugin/index.ts
+   create src/plugin/transformProps.ts
+   create src/types.ts
+   create src/SupersetPluginChartHelloWorld.tsx
+   create test/index.test.ts
+   create test/__mocks__/mockExportString.js
+   create test/plugin/buildQuery.test.ts
+   create test/plugin/transformProps.test.ts
+   create types/external.d.ts
+   create src/images/thumbnail.png
+```
+
+To build the viz plugin, run the following commands:
+
+```
+npm i --force
+npm run build
+```
+
+Alternatively, to run the viz plugin in development mode (=rebuilding whenever changes
+are made), start the dev server with the following command:
+
+```
+npm run dev
+```
+
+To add the package to Superset, go to the `superset-frontend` subdirectory in your
+Superset source folder run
+
+```bash
+npm i -S /tmp/superset-plugin-chart-hello-world
+```
+
+If you publish your package to npm, you can naturally install directly from there, too.
+After this edit the `superset-frontend/src/visualizations/presets/MainPreset.js`
+and make the following changes:
+
+```js
+import { SupersetPluginChartHelloWorld } from 'superset-plugin-chart-hello-world';
+```
+
+to import the viz plugin and later add the following to the array that's passed to the
+`plugins` property:
+
+```js
+new SupersetPluginChartHelloWorld().configure({ key: 'ext-hello-world' }),
+```
+
+After that the viz plugin should show up when you run Superset, e.g. the development
+server:
+
+```bash
+npm run dev-server
+```

superset-frontend/packages/generator-superset/README.md

@@ -36,12 +36,11 @@ npm install -g @superset-ui/generator-superset
 
 ## Usage
 
-Generate a new package or visualization plugin in `@superset-ui`
+Generate a new package or visualization plugin:
 
 ```bash
-cd superset-ui/packages
-mkdir superset-ui-new-package
-cd superset-ui-new-package
+mkdir /tmp/superset-plugin-chart-hello-world
+cd /tmp/superset-plugin-chart-hello-world
 yo @superset-ui/superset
 ```
 

superset-frontend/packages/generator-superset/generators/plugin-chart/index.js

@@ -32,9 +32,7 @@ module.exports = class extends Generator {
         name: 'packageName',
         message: 'Package name:',
         // Default to current folder name
-        default: _.kebabCase(
-          this.appname.replace('superset plugin chart', '').trim(),
-        ),
+        default: _.kebabCase(this.appname),
       },
       {
         type: 'input',
@@ -77,6 +75,7 @@ module.exports = class extends Generator {
     };
 
     [
+      ['gitignore.erb', '.gitignore'],
       ['babel.config.erb', 'babel.config.js'],
       ['jest.config.erb', 'jest.config.js'],
       ['package.erb', 'package.json'],