Automatic TypeScript definition generation from JSG RTTI

.gitignore

@@ -1,3 +1,6 @@
+.idea
+.DS_Store
+
 /rust-deps/target
 /rust-deps/Cargo.toml
 

BUILD.bazel

@@ -1,5 +1,8 @@
 load("@capnp-cpp//src/capnp:cc_capnp_library.bzl", "cc_capnp_library")
 load("@hedron_compile_commands//:refresh_compile_commands.bzl", "refresh_compile_commands")
+load("@aspect_rules_js//npm:defs.bzl", "npm_link_package", "npm_package")
+load("@npm//:defs.bzl", "npm_link_all_packages")
+load("@npm//:capnpc-ts/package_json.bzl", capnpc_ts_bin = "bin")
 
 cc_capnp_library(
     name = "icudata-embed",
@@ -13,3 +16,16 @@ cc_capnp_library(
 refresh_compile_commands(
     name = "refresh_compile_commands",
 )
+
+npm_link_all_packages(name = "node_modules")
+
+npm_link_package(
+    name = "node_modules/@workerd/jsg",
+    src = "//src/workerd/jsg:jsg_js",
+    package = "@workerd/jsg",
+)
+
+capnpc_ts_bin.capnpc_ts_binary(
+    name = "capnpc_ts",
+    visibility = ["//visibility:public"],
+)

WORKSPACE

@@ -153,6 +153,58 @@ load("//rust-deps/cxxbridge_crates:crates.bzl", cxxbridge_repositories = "crate_
 
 cxxbridge_repositories()
 
+# ========================================================================================
+# Node.js bootstrap
+#
+# workerd uses Node.js scripts for generating TypeScript types.
+
+http_archive(
+    name = "aspect_rules_js",
+    sha256 = "b9fde0f20de6324ad443500ae738bda00facbd73900a12b417ce794856e01407",
+    strip_prefix = "rules_js-1.5.0",
+    url = "https://github.com/aspect-build/rules_js/archive/refs/tags/v1.5.0.tar.gz",
+)
+
+http_archive(
+    name = "aspect_rules_ts",
+    sha256 = "743f0e988e4e3f1e25e52c79f9dc3da1ddd77507ae88787ae95b4e70c537872b",
+    strip_prefix = "rules_ts-1.0.0-rc4",
+    url = "https://github.com/aspect-build/rules_ts/archive/refs/tags/v1.0.0-rc4.tar.gz",
+)
+
+load("@aspect_rules_js//js:repositories.bzl", "rules_js_dependencies")
+
+rules_js_dependencies()
+
+load("@rules_nodejs//nodejs:repositories.bzl", "nodejs_register_toolchains")
+
+nodejs_register_toolchains(
+    name = "nodejs",
+    node_version = "18.10.0",
+)
+
+load("@aspect_rules_ts//ts:repositories.bzl", TS_LATEST_VERSION = "LATEST_VERSION", "rules_ts_dependencies")
+
+rules_ts_dependencies(ts_version = TS_LATEST_VERSION)
+
+load("@aspect_rules_js//npm:npm_import.bzl", "npm_translate_lock")
+
+npm_translate_lock(
+    name = "npm",
+    pnpm_lock = "//:pnpm-lock.yaml",
+    # Patches required for `capnp-ts` to type-check
+    patches = {
+        "capnp-ts@0.7.0": ["//:patches/capnp-ts@0.7.0.patch"],
+    },
+    patch_args = {
+        "capnp-ts@0.7.0": ["-p1"],
+    },
+)
+
+load("@npm//:repositories.bzl", "npm_repositories")
+
+npm_repositories()
+
 # ========================================================================================
 # V8 and its dependencies
 #

build/js_capnp_library.bzl

@@ -0,0 +1,124 @@
+"""
+Bazel rule to compile .capnp files into JavaScript using capnp-ts.
+Based on https://github.com/capnproto/capnproto/blob/3b2e368cecc4b1419b40c5970d74a7a342224fac/c++/src/capnp/cc_capnp_library.bzl.
+"""
+
+load("@aspect_rules_js//js:defs.bzl", "js_library")
+
+capnp_provider = provider("Capnproto Provider", fields = {
+    "includes": "includes for this target (transitive)",
+    "inputs": "src + data for the target",
+    "src_prefix": "src_prefix of the target",
+})
+
+def _workspace_path(label, path):
+    if label.workspace_root == "":
+        return path
+    return label.workspace_root + "/" + path
+
+def _capnp_gen_impl(ctx):
+    label = ctx.label
+    src_prefix = _workspace_path(label, ctx.attr.src_prefix)
+    includes = []
+
+    inputs = ctx.files.srcs + ctx.files.data
+    for dep_target in ctx.attr.deps:
+        includes += dep_target[capnp_provider].includes
+        inputs += dep_target[capnp_provider].inputs
+
+    if src_prefix != "":
+        includes.append(src_prefix)
+
+    system_include = ctx.files._capnp_system[0].dirname.removesuffix("/capnp")
+
+    out_dir = ctx.var["GENDIR"]
+    if src_prefix != "":
+        out_dir = out_dir + "/" + src_prefix
+
+    js_out = "-o%s:%s" % (ctx.executable._capnpc_ts.path, out_dir)
+    args = ctx.actions.args()
+    args.add_all(["compile", "--verbose", js_out])
+    args.add_all(["-I" + inc for inc in includes])
+    args.add_all(["-I", system_include])
+    if src_prefix != "":
+        args.add_all(["--src-prefix", src_prefix])
+
+    args.add_all([s for s in ctx.files.srcs])
+
+    ctx.actions.run(
+        inputs = inputs + ctx.files._capnpc_ts + ctx.files._capnpc_capnp + ctx.files._capnp_system,
+        tools = [ctx.executable._capnpc_ts],  # Include required js_binary runfiles
+        outputs = ctx.outputs.outs,
+        executable = ctx.executable._capnpc,
+        arguments = [args],
+        mnemonic = "GenCapnp",
+    )
+
+    return [
+        capnp_provider(
+            includes = includes,
+            inputs = inputs,
+            src_prefix = src_prefix,
+        ),
+    ]
+
+_capnp_gen = rule(
+    attrs = {
+        "srcs": attr.label_list(allow_files = True),
+        "deps": attr.label_list(providers = [capnp_provider]),
+        "data": attr.label_list(allow_files = True),
+        "outs": attr.output_list(),
+        "src_prefix": attr.string(),
+        "_capnpc": attr.label(executable = True, allow_single_file = True, cfg = "exec", default = "@capnp-cpp//src/capnp:capnp_tool"),
+        "_capnpc_ts": attr.label(executable = True, allow_single_file = True, cfg = "exec", default = "//:capnpc_ts"),
+        "_capnpc_capnp": attr.label(executable = True, allow_single_file = True, cfg = "exec", default = "@capnp-cpp//src/capnp:capnpc-capnp"),
+        "_capnp_system": attr.label(default = "@capnp-cpp//src/capnp:capnp_system_library"),
+    },
+    output_to_genfiles = True,
+    implementation = _capnp_gen_impl,
+)
+
+def js_capnp_library(
+        name,
+        srcs = [],
+        data = [],
+        deps = [],
+        src_prefix = "",
+        visibility = None,
+        target_compatible_with = None,
+        **kwargs):
+    """Bazel rule to create a JavaScript capnproto library from capnp source files
+
+    Args:
+        name: library name
+        srcs: list of files to compile
+        data: additional files to provide to the compiler - data files and includes that need not to
+            be compiled
+        deps: other js_capnp_library rules to depend on
+        src_prefix: src_prefix for capnp compiler to the source root
+        visibility: rule visibility
+        target_compatible_with: target compatibility
+        **kwargs: rest of the arguments to js_library rule
+    """
+
+    js_files = [s + ".js" for s in srcs]
+    d_ts_files = [s + ".d.ts" for s in srcs]
+
+    _capnp_gen(
+        name = name + "_gen",
+        srcs = srcs,
+        deps = [s + "_gen" for s in deps],
+        data = data,
+        outs = js_files + d_ts_files,
+        src_prefix = src_prefix,
+        visibility = visibility,
+        target_compatible_with = target_compatible_with,
+    )
+    js_library(
+        name = name,
+        srcs = js_files + d_ts_files,
+        deps = deps + ["//:node_modules/capnp-ts"],
+        visibility = visibility,
+        target_compatible_with = target_compatible_with,
+        **kwargs
+    )

package.json

@@ -0,0 +1,25 @@
+{
+  "name": "@cloudflare/workerd-root",
+  "private": true,
+  "scripts": {
+    "lint": "eslint types/src"
+  },
+  "dependencies": {
+    "capnp-ts": "^0.7.0",
+    "prettier": "^2.7.1",
+    "typescript": "~4.7.4"
+  },
+  "devDependencies": {
+    "@types/debug": "^4.1.7",
+    "@types/node": "^18.7.18",
+    "@types/prettier": "^2.7.1",
+    "@typescript-eslint/eslint-plugin": "^5.37.0",
+    "@typescript-eslint/parser": "^5.37.0",
+    "capnpc-ts": "^0.7.0",
+    "esbuild": "^0.15.7",
+    "eslint": "^8.22.0",
+    "eslint-config-prettier": "^8.5.0",
+    "eslint-plugin-import": "^2.26.0",
+    "eslint-plugin-prettier": "^4.2.1"
+  }
+}

patches/capnp-ts@0.7.0.patch

@@ -0,0 +1,11 @@
+--- a/src/serialization/pointers/struct.ts
++++ b/src/serialization/pointers/struct.ts
+@@ -107,8 +107,6 @@ export class Struct extends Pointer {
+   static readonly setText = setText;
+   static readonly testWhich = testWhich;
+
+-  readonly _capnp!: _Struct;
+-
+   /**
+    * Create a new pointer to a struct.
+    *