From b6213c5a2f89f353fd848a78afa0636e5dee793a Mon Sep 17 00:00:00 2001
From: Paul Gschwendtner <paulgschwendtner@gmail.com>
Date: Thu, 16 Jun 2022 12:55:56 +0000
Subject: [PATCH] feat(bazel/spec-bundling): support bundling ESM into CJS for
 legacy tests like protractor

---
 bazel/spec-bundling/index.bzl        | 41 +++++++++++++++++++---------
 bazel/spec-bundling/test/BUILD.bazel | 14 ++++++++++
 tsconfig.json                        |  1 +
 3 files changed, 43 insertions(+), 13 deletions(-)

diff --git a/bazel/spec-bundling/index.bzl b/bazel/spec-bundling/index.bzl
index 02db12727..40ecd3116 100644
--- a/bazel/spec-bundling/index.bzl
+++ b/bazel/spec-bundling/index.bzl
@@ -1,5 +1,5 @@
 load("@build_bazel_rules_nodejs//:index.bzl", "js_library")
-load("//bazel/esbuild:index.bzl", "esbuild_amd", "esbuild_config", "esbuild_esm_bundle")
+load("//bazel/esbuild:index.bzl", "esbuild", "esbuild_amd", "esbuild_config", "esbuild_esm_bundle")
 load("//bazel/spec-bundling:spec-entrypoint.bzl", "spec_entrypoint")
 load("//bazel/spec-bundling:bundle-config.bzl", "spec_bundle_config_file")
 
@@ -12,8 +12,8 @@ def spec_bundle(
         # We cannot use `ES2017` or higher as that would result in `async/await` not being downleveled.
         # ZoneJS needs to be able to intercept these as otherwise change detection would not work properly.
         target = "es2016",
-        workspace_name = None,
-        **kwargs):
+        external = [],
+        workspace_name = None):
     """Macro that will bundle all test files with their respective transitive dependencies.
 
     Bundled specs end up in a single bundle file that can be loaded within Karma or NodeJS directly.
@@ -24,17 +24,21 @@ def spec_bundle(
         name: Name of the spec bundle target
         deps: Targets that contain all spec files. Files ending with `spec.js`
           are picked up.
-        platform: Platform for which spec should be bundled. i.e. `node` or `browser`.
+        platform: Platform for which spec should be bundled. i.e. `node`, `browser` or `cjs-legacy`.
         bootstrap: Targets providing bootstrap scripts that run before the specs. Files
           ending with `init.js` are picked up.
         target: Target ECMAScript to use for the specs bundle.
         run_angular_linker: Whether the Angular linker should process the bundled code.
+        external: List of modules/packages which should not be bundled.
         workspace_name: Workspace name that needs to be provided for the AMD module name.
-        **kwargs: Other arguments to be passed to ESBuild.
     """
 
     is_browser_test = platform == "browser"
+    is_legacy_cjs = platform == "cjs-legacy"
+    is_node = platform == "node"
+
     package_name = native.package_name()
+    esbuild_attrs = dict()
 
     spec_entrypoint(
         name = "%s_spec_entrypoint" % name,
@@ -61,23 +65,34 @@ def spec_bundle(
         fail("The spec-bundling target %s is declared as browser test. In order to be able " +
              "to construct an AMD module name, the `workspace_name` attribute needs to be set.")
 
-    # Browser tests (Karma) need named AMD modules to load.
-    # TODO(devversion): consider updating `@bazel/concatjs` to support loading JS files directly.
-    esbuild_rule = esbuild_amd if is_browser_test else esbuild_esm_bundle
-    amd_name = "%s/%s/%s" % (workspace_name, package_name, name + "_spec") if is_browser_test else None
+    esbuild_rule = None
+
+    if is_browser_test:
+        esbuild_rule = esbuild_amd
+        amd_name = "%s/%s/%s" % (workspace_name, package_name, name + "_spec")
+        esbuild_attrs["platform"] = "browser"
+        esbuild_attrs["output"] = "%s_spec.js" % name
+        esbuild_attrs["module_name"] = amd_name
+    elif is_legacy_cjs:
+        esbuild_rule = esbuild
+        esbuild_attrs["format"] = "iife"
+        esbuild_attrs["platform"] = "node"
+        esbuild_attrs["output"] = "%s_spec.js" % name
+    elif is_node:
+        esbuild_rule = esbuild_esm_bundle
+        esbuild_attrs["platform"] = "node"
+        esbuild_attrs["output"] = "%s_spec.mjs" % name
 
     esbuild_rule(
         name = "%s_bundle" % name,
         testonly = True,
         config = ":%s_config" % name,
-        output = "%s_spec.%s" % (name, "js" if is_browser_test else "mjs"),
         entry_point = ":%s_spec_entrypoint" % name,
-        module_name = amd_name,
         target = target,
-        platform = platform,
         deps = deps + [":%s_spec_entrypoint" % name],
         link_workspace_root = True,
-        **kwargs
+        external = external,
+        **esbuild_attrs
     )
 
     js_library(
diff --git a/bazel/spec-bundling/test/BUILD.bazel b/bazel/spec-bundling/test/BUILD.bazel
index ac5cc0213..d7e3bbfe3 100644
--- a/bazel/spec-bundling/test/BUILD.bazel
+++ b/bazel/spec-bundling/test/BUILD.bazel
@@ -20,9 +20,23 @@ spec_bundle(
     deps = [":test_lib"],
 )
 
+spec_bundle(
+    name = "test_bundle_legacy_cjs",
+    platform = "cjs-legacy",
+    run_angular_linker = True,
+    deps = [":test_lib"],
+)
+
 jasmine_node_test(
     name = "test",
     deps = [
         ":test_bundle",
     ],
 )
+
+jasmine_node_test(
+    name = "test_legacy_cjs",
+    deps = [
+        ":test_bundle_legacy_cjs",
+    ],
+)
diff --git a/tsconfig.json b/tsconfig.json
index 786db6599..3ca1b31d4 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -8,6 +8,7 @@
     "outDir": "./dist/tsc-non-bazel-out",
     "skipLibCheck": true,
     "noImplicitOverride": true,
+    // TODO(ESM): Remove this when Bazel also uses the Node resolution.
     "esModuleInterop": true,
     "noImplicitReturns": true
   },