Stop using module.createRequire (problematic under webpack), incorporate and export resolveModule helper from markdownlint-cli2.

test/resolve-module-test.mjs

@@ -0,0 +1,147 @@
+// @ts-check
+
+import test from "ava";
+import path from "node:path";
+import { __dirname as getDirname } from "./esm-helpers.mjs";
+import { resolveModule, resolveModuleCustomResolve } from "../lib/resolve-module.cjs";
+
+import { createRequire } from "node:module";
+const require = createRequire(import.meta.url);
+// eslint-disable-next-line no-underscore-dangle
+const __dirname = getDirname(import.meta);
+
+test("built-in module", (t) => {
+  t.plan(1);
+  t.deepEqual(
+    resolveModule("node:fs"),
+    require.resolve("node:fs")
+  );
+});
+
+test("locally-installed module", (t) => {
+  t.plan(1);
+  t.deepEqual(
+    resolveModule("micromark"),
+    require.resolve("micromark")
+  );
+});
+
+test("absolute path to module", (t) => {
+  t.plan(1);
+  const absolute =
+    path.resolve(
+      __dirname,
+      "./rules/node_modules/markdownlint-rule-sample-commonjs"
+    );
+  t.deepEqual(
+    resolveModule(absolute),
+    require.resolve(absolute)
+  );
+});
+
+test("relative (to __dirname) path to module", (t) => {
+  t.plan(1);
+  t.deepEqual(
+    resolveModule(
+      "./rules/node_modules/markdownlint-rule-sample-module",
+      // __dirname is needed because require.resolve is relative to this
+      // file while resolveModule is relative to resolve-module.cjs
+      [ __dirname ]
+    ),
+    require.resolve(
+      "./rules/node_modules/markdownlint-rule-sample-module"
+    )
+  );
+});
+
+test("module in alternate node_modules", (t) => {
+  t.plan(3);
+  t.throws(
+    () => require.resolve("markdownlint-rule-sample-commonjs"),
+    { "code": "MODULE_NOT_FOUND" }
+  );
+  t.throws(
+    () => resolveModule("markdownlint-rule-sample-commonjs"),
+    { "code": "MODULE_NOT_FOUND" }
+  );
+  t.deepEqual(
+    resolveModule(
+      "markdownlint-rule-sample-commonjs",
+      [ path.join(__dirname, "rules") ]
+    ),
+    require.resolve(
+      "markdownlint-rule-sample-commonjs",
+      { "paths": [ path.join(__dirname, "rules") ] }
+    )
+  );
+});
+
+test("module local, relative, and in alternate node_modules (same paths)", (t) => {
+  t.plan(3);
+  const paths = [
+    __dirname,
+    path.join(__dirname, "rules")
+  ];
+  t.deepEqual(
+    resolveModule(
+      "micromark",
+      paths
+    ),
+    require.resolve(
+      "micromark",
+      { paths }
+    )
+  );
+  t.deepEqual(
+    resolveModule(
+      "./rules/node_modules/markdownlint-rule-sample-commonjs",
+      paths
+    ),
+    require.resolve(
+      "./rules/node_modules/markdownlint-rule-sample-commonjs",
+      { paths }
+    )
+  );
+  t.deepEqual(
+    resolveModule(
+      "markdownlint-rule-sample-commonjs",
+      paths
+    ),
+    require.resolve(
+      "markdownlint-rule-sample-commonjs",
+      { paths }
+    )
+  );
+});
+
+test("custom resolve implementation", (t) => {
+  t.plan(1);
+  const expected =
+    require.resolve("./rules/node_modules/markdownlint-rule-sample-module");
+  const customResolve = (id, options) => require.resolve(id, options);
+  customResolve.paths = (request) => require.resolve.paths(request);
+  t.deepEqual(
+    resolveModuleCustomResolve(
+      customResolve,
+      "./rules/node_modules/markdownlint-rule-sample-module",
+      [ __dirname ]
+    ),
+    expected
+  );
+});
+
+test("custom resolve implementation, missing paths", (t) => {
+  t.plan(1);
+  const expected =
+    require.resolve("./rules/node_modules/markdownlint-rule-sample-commonjs");
+  const customResolve = (id, options) => require.resolve(id, options);
+  t.deepEqual(
+    resolveModuleCustomResolve(
+      // @ts-ignore
+      customResolve,
+      "./rules/node_modules/markdownlint-rule-sample-commonjs",
+      [ __dirname ]
+    ),
+    expected
+  );
+});