This is a sub-tracking issue of #234

This is a component of Redwood's initiative to add first-class TypeScript support. 🎉

Generators are a part of the CLI package and located in this directory:
https://github.com/redwoodjs/redwood/tree/master/packages/cli/src/commands/generate

The CLI package is built with Yargs. Read more here.

Goal

The intention is to provide a path for a collaborative, incremental transition to having 100% TypeScript generators. This means the scope of a PR can be an individual generator, which can be merged into the master branch on its own when it's ready.

• source templates will be .ts
• generators should be aware of both .ts and .js; this applies to 1) refusing to run if files already exist and 2) overwriting existing files using --force
  • In the case where existing files are a different language target (e.g. in the case of a hybrid-project), the generator should refuse to run regardless of using the --force option; a clear explanation message should be given
• templates should be transpiled and formatted when the target language is JS (suggested to use ts.transpile and prettier, but this needs evaluation)
  • need to determine appropriate ts.ScriptTarget; "ESNext" seems like a candidate
  • ⚠️transpilation formatting goal == match existing JS templates so that no updates are required for Redwood Tutorial, either code snippets or images (TBD as needed)
• generators should have CLI options for targeting --javascript or --typescript
  • generators should not require a language target option; instead, the default target will be the project "language default" or a config override in redwood.toml if given.
  • Example: if tsconfig.json exists and there is no redwood.toml override, the generator will automatically set --typescript to true. Therefore, running yarn rw g [option] will target typescript.
  • TODO: create a new Internal package helper for easy access to this config value
• generators need to pass CI tests and the generated ...test.ts|js files need to pass yarn rw test and yarn rw lint

Steps to Convert a Specific Generator

1. Rewrite each generator template, including template test file, as TS
   • TS files will replace JS files
2. Convert corresponding __tests__ directory files and fixtures to TS
3. Add a JS and TS target CLI command option, e.g. [--javascript|--typescript] to each generator CLI command
   • commands should also be aliased [-js|-ts] respectively
   • set the behavior to automatically use the project "language default" (see above) OR a given --javascript or --typescript option
4. When language target=javascript, transpile and format TS templates to JS

• do generated ..test.ts/js files pass yarn rw lint and yarn rw test?

Checklist: Templates and Generators

• Destroy (New command in progress via Add destroy command #487)
  • confirm support for both ts and js filetypes, as well as hybrid Apps
  • add support as/if needed
• Helpers (PR CLI: Convert helpers and src/lib to ts #557 stalled out)
  • convert __tests__/helpers.test.js to TS
  • convert helpers.js to TS
• src/lib Files
  note: these files are outside generators/, but the functionality that relates to generators should be moved to src/commands/generators
  • src/lib/colors.js
  • src/lib/index.js
  • src/lib/test.js
• Component Convert component generator to TS #632
  • convert templates/ files to TS
  • convert __tests__/ fixtures and test.js to TS
  • generator support for JS transpilation; enable --javascript as default
• Function
  • convert templates/ file to TS
  • convert __tests__/ fixtures and test.js to TS
  • generator support for JS transpilation; enable --javascript as default
• Layout Convert layout generator to TypeScript #685
  • convert templates/ files to TS
  • convert __tests__/ fixtures and test.js to TS
  • generator support for JS transpilation; enable --javascript as default
• Page
  ⚠️ requires updates to Router to support TS
  • convert templates/ files to TS
  • convert __tests__/ fixtures and test.js to TS
  • generator support for JS transpilation; enable --javascript as default
• SDL 👉PR enable typescript services and sdl #515
  • convert templates/ file to TS
  • convert __tests__/ fixtures and test.js to TS
  • generator support for JS transpilation; enable --javascript as default
• Service 👉PR enable typescript services and sdl #515
  • convert templates/ files to TS
  • convert __tests__/ fixtures and test.js to TS
  • generator support for JS transpilation; enable --javascript as default
• Cell
  ⚠️ requires additional support to replicate functionality in TS. Details in this comment.
  • convert templates/ files to TS
  • convert __tests__/ fixtures and test.js to TS
  • generator support for JS transpilation; enable --javascript as default
• Scaffold
  ⚠️ requires SDL, Service, and Cells TS conversion
  ⚠️ requires updates to Router to support TS
  • convert templates/ files to TS: components, layouts, and pages
  • convert __tests__/ fixtures and test.js to TS
  • generator support for JS transpilation; enable --javascript as default