fix #3485: map subpath imports to node built-ins

CHANGELOG.md

@@ -60,6 +60,31 @@
     }
     ```
 
+* Allow package subpath imports to map to node built-ins ([#3485](https://github.com/evanw/esbuild/issues/3485))
+
+    You are now able to use a [subpath import](https://nodejs.org/api/packages.html#subpath-imports) in your package to resolve to a node built-in module. For example, with a `package.json` file like this:
+
+    ```json
+    {
+      "type": "module",
+      "imports": {
+        "#stream": {
+          "node": "stream",
+          "default": "./stub.js"
+        }
+      }
+    }
+    ```
+
+    You can now import from node's `stream` module like this:
+
+    ```js
+    import * as stream from '#stream';
+    console.log(Object.keys(stream));
+    ```
+
+    This will import from node's `stream` module when the platform is `node` and from `./stub.js` otherwise.
+
 * No longer throw an error when a `Symbol` is missing ([#3453](https://github.com/evanw/esbuild/issues/3453))
 
     Certain JavaScript syntax features use special properties on the global `Symbol` object. For example, the asynchronous iteration syntax uses `Symbol.asyncIterator`. Previously esbuild's generated code for older browsers required this symbol to be polyfilled. However, starting with this release esbuild will use [`Symbol.for()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/for) to construct these symbols if they are missing instead of throwing an error about a missing polyfill. This means your code no longer needs to include a polyfill for missing symbols as long as your code also uses `Symbol.for()` for missing symbols.

internal/bundler_tests/bundler_packagejson_test.go

@@ -2873,3 +2873,38 @@ func TestPackageJsonDisabledTypeModuleIssue3367(t *testing.T) {
 		},
 	})
 }
+
+// See: https://github.com/evanw/esbuild/issues/3485
+func TestPackageJsonSubpathImportNodeBuiltinIssue3485(t *testing.T) {
+	packagejson_suite.expectBundled(t, bundled{
+		files: map[string]string{
+			"/entry.js": `
+				import fs from '#fs'
+				import http from '#http'
+				fs.readFileSync()
+				http.createServer()
+			`,
+			"/package.json": `
+				{
+					"imports": {
+						"#fs": {
+							"node": "fs",
+							"default": "./empty.js"
+						},
+						"#http": {
+							"node": "node:http",
+							"default": "./empty.js"
+						}
+					}
+				}
+			`,
+			"/empty.js": ``,
+		},
+		entryPaths: []string{"/entry.js"},
+		options: config.Options{
+			Mode:          config.ModeBundle,
+			Platform:      config.PlatformNode,
+			AbsOutputFile: "/out.js",
+		},
+	})
+}

internal/bundler_tests/snapshots/snapshots_packagejson.txt

@@ -843,6 +843,15 @@ console.log("pkg3");
 // tmp/pkg/@scope/pkg4/bat.js
 console.log("pkg4");
 
+================================================================================
+TestPackageJsonSubpathImportNodeBuiltinIssue3485
+---------- /out.js ----------
+// entry.js
+import fs from "fs";
+import http from "node:http";
+fs.readFileSync();
+http.createServer();
+
 ================================================================================
 TestPackageJsonTypeShouldBeTypes
 ---------- /Users/user/project/out.js ----------