revert implicit /+esm for .js (#1186)

Author: mbostock

src/npm.ts

@@ -6,7 +6,7 @@ import {simple} from "acorn-walk";
 import {rsort, satisfies} from "semver";
 import {isEnoent} from "./error.js";
 import type {ExportNode, ImportNode, ImportReference} from "./javascript/imports.js";
-import {isImportMetaResolve, isJavaScript, parseImports} from "./javascript/imports.js";
+import {isImportMetaResolve, parseImports} from "./javascript/imports.js";
 import {parseProgram} from "./javascript/parse.js";
 import type {StringLiteral} from "./javascript/source.js";
 import {getStringLiteralValue, isStringLiteral} from "./javascript/source.js";
@@ -262,7 +262,7 @@ export async function resolveNpmImport(root: string, specifier: string): Promise
   } = parseNpmSpecifier(specifier);
   const version = await resolveNpmVersion(root, {name, range});
   return `/_npm/${name}@${version}/${
-    (extname(path) && !isJavaScript(path)) || // npm:foo/bar.css
+    extname(path) || // npm:foo/bar.js or npm:foo/bar.css
     path === "" || // npm:foo/
     path.endsWith("/") // npm:foo/bar/
       ? path

test/npm-test.ts

@@ -10,13 +10,13 @@ describe("getDependencyResolver(root, path, input)", () => {
     const root = "test/input/build/simple-public";
     const specifier = "/npm/[email protected]/dist/d3-array.js";
     const resolver = await getDependencyResolver(root, "/_npm/[email protected]/_esm.js", `import '${specifier}';\n`); // prettier-ignore
-    assert.strictEqual(resolver(specifier), "../[email protected]/dist/d3-array.js._esm.js");
+    assert.strictEqual(resolver(specifier), "../[email protected]/dist/d3-array.js");
   });
   it("finds /npm/ import resolutions and re-resolves their versions", async () => {
     const root = "test/input/build/simple-public";
     const specifier = "/npm/[email protected]/dist/d3-array.js";
     const resolver = await getDependencyResolver(root, "/_npm/[email protected]/_esm.js", `import.meta.resolve('${specifier}');\n`); // prettier-ignore
-    assert.strictEqual(resolver(specifier), "../[email protected]/dist/d3-array.js._esm.js");
+    assert.strictEqual(resolver(specifier), "../[email protected]/dist/d3-array.js");
   });
 });
 
@@ -55,14 +55,14 @@ describe("resolveNpmImport(root, specifier)", () => {
     assert.strictEqual(await resolveNpmImport(root, "d3-array/foo+bar"), "/_npm/[email protected]/foo+bar._esm.js");
     assert.strictEqual(await resolveNpmImport(root, "d3-array/foo+esm"), "/_npm/[email protected]/foo+esm._esm.js");
   });
-  it("implicitly adds ._esm.js for specifiers with a JavaScript extension", async () => {
-    assert.strictEqual(await resolveNpmImport(root, "d3-array/src/index.js"), "/_npm/[email protected]/src/index.js._esm.js"); // prettier-ignore
-  });
   it("replaces /+esm with /_esm.js or ._esm.js", async () => {
     assert.strictEqual(await resolveNpmImport(root, "d3-array/+esm"), "/_npm/[email protected]/_esm.js");
     assert.strictEqual(await resolveNpmImport(root, "d3-array/src/+esm"), "/_npm/[email protected]/src._esm.js");
     assert.strictEqual(await resolveNpmImport(root, "d3-array/src/index.js/+esm"), "/_npm/[email protected]/src/index.js._esm.js"); // prettier-ignore
   });
+  it("does not add ._esm.js for specifiers with a JavaScript extension", async () => {
+    assert.strictEqual(await resolveNpmImport(root, "d3-array/src/index.js"), "/_npm/[email protected]/src/index.js");
+  });
   it("does not add ._esm.js for specifiers with a non-JavaScript extension", async () => {
     assert.strictEqual(await resolveNpmImport(root, "d3-array/src/index.css"), "/_npm/[email protected]/src/index.css");
   });