Gazelle extension for TypeScript

[gregmagolan]

Replaces aspect-build/rules_js#20

[wtgtybhertgeghgtwtg]

I've been trying my hand at this, but it's fraught with speedbumps.

• Gazelle requires extensions to be built in Go. There was talk about a plugin to support other languages, but it seems to have stalled.
• Since esbuild doesn't expose its parser and I can't seem to find any other parser in Go-space, I've been statically linking a Rust binary that uses swc. Since swc has a library to grab dependencies, this part is surprisingly straightforward.
• rules_go has issues with IDE support for cgo, so errors around the bindings on the Go side just have to be ignored.
• The ecosystem does not have go-to rules for certain tasks like linting or formatting like other languages. I've mostly had to resolve to some internal macros for those, but they are not portable.
  Right now, I've got it far enough that it can spit out something like

load("@aspect_rules_js//npm:defs.bzl", "npm_package")
load("@aspect_rules_ts//ts:defs.bzl", "ts_config")
load("@npm_dependencies//:defs.bzl", "npm_link_all_packages")
load("//macros/eslint-test:eslint_test.bzl", "eslint_test")
load("//macros/transpile-typescript:transpile_typescript.bzl", "transpile_typescript")
 
npm_link_all_packages(name = "node_modules")

ts_config(
    name = "tsconfig",
    src = "tsconfig.json",
)

transpile_typescript(
    name = "typescript",
    srcs = ["source/render-package-json.ts"],
    package_json = "package.json",
    tsconfig = ":tsconfig",
    deps = [":node_modules/sort-keys"],
)

npm_package(
    name = "render-package-json",
    srcs = [":typescript"],
    visibility = ["//visibility:public"],
)

eslint_test(
    name = "eslint_test",
    srcs = ["source/render-package-json.ts"],
    eslintrc = ".eslintrc.cjs",
    package_json = "package.json",
    tsconfig = ":tsconfig",
    deps = [":node_modules/sort-keys"],
)

but it's hacky and nowhere near close enough for a PR. If the trade-offs above are acceptable for now, is there a design document I can conform to while cleaning it up and submit a proof of concept?

[alexeagle]

Hi @wtgtybhertgeghgtwtg you made some good progress there!

I'm sorry we didn't update this issue sooner - right now we are planning to make the gazelle extension licensed differently from rules_ts so that we have some way to pay our engineers.

It does use esbuild's parser, with a little trick to get at the needed API.

We have that in a private repo, are you interested in collaborating on it despite that?

[wtgtybhertgeghgtwtg]

Most of the work I have has been with swc and linking side of things, so I doubt I'd be of much use if you've found an esbuild setup. Thank you for the offer, however.

[gregmagolan]

We are close to releasing this feature with the Aspect CLI. Closing this issue as we are developing it closed source in our monorepo.