feat: Allow importing .cjs files (#25426)

This commit adds support for executing top-level `.cjs` files, 
as well as import `.cjs` files from within npm packages.

This works only for `.cjs` files, the contents of sibling `package.json`
are not consulted for the `"type"` field.

Closes https://github.com/denoland/deno/issues/25384

---------

Signed-off-by: David Sherret <dsherret@users.noreply.github.com>
Co-authored-by: Luca Casonato <hello@lcas.dev>
Co-authored-by: David Sherret <dsherret@users.noreply.github.com>

cli/resolver.rs

@@ -327,7 +327,9 @@ impl NpmModuleLoader {
     specifier: &ModuleSpecifier,
     maybe_referrer: Option<&ModuleSpecifier>,
   ) -> Option<Result<ModuleCodeStringSource, AnyError>> {
-    if self.node_resolver.in_npm_package(specifier) {
+    if self.node_resolver.in_npm_package(specifier)
+      || (specifier.scheme() == "file" && specifier.path().ends_with(".cjs"))
+    {
       Some(self.load(specifier, maybe_referrer).await)
     } else {
       None
@@ -376,7 +378,9 @@ impl NpmModuleLoader {
         }
       })?;
 
-    let code = if self.cjs_resolutions.contains(specifier) {
+    let code = if self.cjs_resolutions.contains(specifier)
+      || (specifier.scheme() == "file" && specifier.path().ends_with(".cjs"))
+    {
       // translate cjs to esm if it's cjs and inject node globals
       let code = match String::from_utf8_lossy(&code) {
         Cow::Owned(code) => code,

tests/integration/run_tests.rs

@@ -1926,11 +1926,6 @@ itest!(es_private_fields {
   output: "run/es_private_fields.js.out",
 });
 
-itest!(cjs_imports {
-  args: "run --quiet --reload run/cjs_imports/main.ts",
-  output: "run/cjs_imports/main.out",
-});
-
 itest!(ts_import_from_js {
   args: "run --quiet --reload run/ts_import_from_js/main.js",
   output: "run/ts_import_from_js/main.out",

tests/specs/run/import_common_js/__test__.jsonc

@@ -0,0 +1,6 @@
+{
+  "steps": [
+    { "args": "run -R index.cjs", "output": "index.out" },
+    { "args": "run -R main.ts", "output": "main.out" }
+  ]
+}

tests/specs/run/import_common_js/a.js

@@ -0,0 +1,7 @@
+function foobar() {
+  console.log("foobar");
+}
+
+module.exports = {
+  foobar,
+};

tests/specs/run/import_common_js/index.cjs

@@ -0,0 +1,9 @@
+const process = require("process");
+const a = require("./a");
+
+console.log(process.cwd());
+
+module.exports = {
+  cwd: process.cwd,
+  foobar: a.foobar,
+};

tests/specs/run/import_common_js/index.out

@@ -0,0 +1 @@
+[WILDCARD]import_common_js

tests/specs/run/import_common_js/main.out

@@ -0,0 +1,5 @@
+hello from foo node module
+[WILDCARD]import_common_js
+cjsModule.cwd() [WILDCARD]import_common_js
+foobar
+cjsModule.foobar() undefined

tests/specs/run/import_common_js/main.ts

@@ -0,0 +1,3 @@
+import foo from "foo";
+
+foo();

tests/specs/run/import_common_js/node_modules/foo/index.mjs

@@ -0,0 +1,14 @@
+import process from "node:process";
+import path from "node:path";
+import url from "node:url";
+
+export default async function () {
+    console.log("hello from foo node module");
+
+    const cjsFileToImport = path.join(process.cwd(), "index.cjs");
+
+    const cjsModule = await import(url.pathToFileURL(cjsFileToImport));
+
+    console.log("cjsModule.cwd()", cjsModule.cwd());
+    console.log("cjsModule.foobar()", cjsModule.foobar());
+}

tests/specs/run/import_common_js/node_modules/foo/package.json

@@ -0,0 +1,3 @@
+{
+    "main": "./index.mjs"
+}

tests/specs/run/import_common_js/package.json

@@ -0,0 +1,5 @@
+{
+  "dependencies": {
+    "foo": "*"
+  }
+}

tests/testdata/run/cjs_imports/commonjs.cjs

@@ -1 +0,0 @@
-console.log("Hello World");

tests/testdata/run/cjs_imports/main.out

@@ -1 +0,0 @@
-Hello World

tests/testdata/run/cjs_imports/main.ts

@@ -1 +0,0 @@
-import "./commonjs.cjs";

tools/lint.js

@@ -221,7 +221,7 @@ async function ensureNoNewITests() {
     "pm_tests.rs": 0,
     "publish_tests.rs": 0,
     "repl_tests.rs": 0,
-    "run_tests.rs": 349,
+    "run_tests.rs": 348,
     "shared_library_tests.rs": 0,
     "task_tests.rs": 30,
     "test_tests.rs": 75,