From c2375d55c04bc05c0921efd25090fbe3122b824b Mon Sep 17 00:00:00 2001
From: Doug Parker <dgp1130@users.noreply.github.com>
Date: Mon, 27 Feb 2023 19:14:39 -0800
Subject: [PATCH] WIP: Fix rules.

---
 common/paths.bzl                              | 24 +++++++++++++++++++
 .../rules_prerender/prerender_component.bzl   | 15 ++++++------
 .../prerender_pages_unbundled.bzl             |  7 ++----
 3 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/common/paths.bzl b/common/paths.bzl
index e032e909..7deaa138 100644
--- a/common/paths.bzl
+++ b/common/paths.bzl
@@ -5,3 +5,27 @@ visibility("public")
 def is_js_file(src):
     """Returns whether or not the given src path is a JavaScript file."""
     return src.endswith(".js") or src.endswith(".mjs") or src.endswith(".cjs")
+
+def is_ts_file(src):
+    return src.endswith(".ts") or src.endswith(".mts") or src.endswith(".cts")
+
+def is_ts_declaration_file(src):
+    return src.endswith(".d.ts") or src.endswith(".d.mts") or src.endswith(".d.cts")
+
+def js_output(src):
+    parts = src.split(".")
+    rest = parts[:-1]
+    ext = parts[-1]
+    js_ext = _to_js_extension(ext)
+
+    return ".".join(rest) + "." + js_ext
+
+def _to_js_extension(ext):
+    if ext == "ts":
+        return "js"
+    elif ext == "mts":
+        return "mjs"
+    elif ext == "cts":
+        return "cjs"
+    else:
+        fail("Expected a `[mc]?ts` extension, but got `%s`." % ext)
diff --git a/packages/rules_prerender/prerender_component.bzl b/packages/rules_prerender/prerender_component.bzl
index 9d8e58e0..7f1de45a 100644
--- a/packages/rules_prerender/prerender_component.bzl
+++ b/packages/rules_prerender/prerender_component.bzl
@@ -4,7 +4,7 @@ load("@aspect_rules_js//js:defs.bzl", "js_library")
 load("@aspect_rules_js//js:providers.bzl", "JsInfo", "js_info")
 load("@aspect_rules_ts//ts:defs.bzl", "ts_project")
 load("//common:label.bzl", "absolute")
-load("//common:paths.bzl", "is_js_file")
+load("//common:paths.bzl", "is_js_file", "is_ts_file", "is_ts_declaration_file")
 load("//packages/rules_prerender/css:css_binaries.bzl", "css_binaries")
 load("//packages/rules_prerender/css:css_group.bzl", "css_group")
 load(":web_resources.bzl", "web_resources")
@@ -39,10 +39,11 @@ def prerender_component(
     
     Args:
         name: The name of this rule.
-        srcs: The source files for use in prerendering. May be `*.ts` files or
-            `*.js`/`*.mjs`/`*.cjs`. All source files must be JavaScript, or all
-            source files must be TypeScript. However, mixing the two is not
-            allowed. `*.d.ts` files are also allowed in either case.
+        srcs: The source files for use in prerendering. May be
+            `*.ts`/`*.mts`/`*.cts` or `*.js`/`*.mjs`/`*.cjs` files. All source
+            files must be JavaScript, or all source files must be TypeScript.
+            However, mixing the two is not allowed. `*.d.ts` files are also
+            allowed in either case.
         tsconfig: A label referencing a tsconfig.json file or `ts_config()`
             target. Will be used to compile `*.ts` files in `srcs`.
         source_map: A boolean indicating whether or not to generate source maps for
@@ -79,7 +80,7 @@ def prerender_component(
     """
 
     prerender_lib = "%s_prerender" % name
-    if all([src.endswith(".ts") or src.endswith(".d.ts") for src in srcs]):
+    if all([is_ts_file(src) for src in srcs]):
         ts_project(
             name = prerender_lib,
             srcs = srcs,
@@ -93,7 +94,7 @@ def prerender_component(
             testonly = testonly,
             visibility = visibility,
         )
-    elif all([is_js_file(src) or src.endswith(".d.ts") for src in srcs]):
+    elif all([is_js_file(src) or is_ts_declaration_file(src) for src in srcs]):
         if tsconfig:
             fail("Cannot set a `tsconfig.json` file for a JS-based" +
                 " `prerender_component()`, don't set the `tsconfig` attribute.")
diff --git a/packages/rules_prerender/prerender_pages_unbundled.bzl b/packages/rules_prerender/prerender_pages_unbundled.bzl
index 975d0890..658d3f7c 100644
--- a/packages/rules_prerender/prerender_pages_unbundled.bzl
+++ b/packages/rules_prerender/prerender_pages_unbundled.bzl
@@ -2,6 +2,7 @@
 
 load("@aspect_rules_js//js:defs.bzl", "js_library")
 load("//common:label.bzl", "absolute", "file_path_of", "rel_path")
+load("//common:paths.bzl", "js_output")
 load(":prerender_component.bzl", "prerender_component")
 load(":prerender_resources.bzl", "prerender_resources_internal")
 load(":script_entry_point.bzl", "script_entry_points")
@@ -121,11 +122,7 @@ def prerender_pages_unbundled(
 
     # Execute the runner to generate annotated resources.
     annotated = "%s_annotated" % name
-    js_src = (
-        ".ts".join(src.split(".ts")[:-1]) + ".js"
-        if src.endswith(".ts")
-        else src
-    )
+    js_src = js_output(src)
     prerender_resources_internal(
         name = annotated,
         entry_point = rel_path(file_path_of(absolute(js_src))),