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
+  );
+});

test/rules/node_modules/markdownlint-rule-sample-commonjs/package.json

@@ -0,0 +1,14 @@
+{
+  "name": "markdownlint-rule-sample-commonjs",
+  "version": "0.0.1",
+  "description": "Package for markdownlint custom rule sample (commonjs)",
+  "main": "sample-rule.cjs",
+  "type": "commonjs",
+  "author": "David Anson (https://dlaa.me/)",
+  "homepage": "https://github.com/DavidAnson/markdownlint",
+  "license": "MIT",
+  "keywords": [
+    "markdownlint-rule"
+  ],
+  "private": true
+}

test/rules/node_modules/markdownlint-rule-sample-commonjs/sample-rule.cjs

@@ -0,0 +1,18 @@
+// @ts-check
+
+"use strict";
+
+module.exports = {
+  "names": [ "sample-rule-commonjs" ],
+  "description": "Sample rule (commonjs)",
+  "tags": [ "sample" ],
+  "function": (params, onError) => {
+    const hrTokens = params.tokens.filter((token) => token.type === "hr");
+    for (const token of hrTokens) {
+      onError({
+        "lineNumber": token.lineNumber,
+        "detail": "Sample error for hr"
+      });
+    }
+  }
+};

test/rules/node_modules/markdownlint-rule-sample-module/package.json

@@ -0,0 +1,14 @@
+{
+  "name": "markdownlint-rule-sample-module",
+  "version": "0.0.1",
+  "description": "Package for markdownlint custom rule sample (module)",
+  "main": "sample-rule.mjs",
+  "type": "module",
+  "author": "David Anson (https://dlaa.me/)",
+  "homepage": "https://github.com/DavidAnson/markdownlint",
+  "license": "MIT",
+  "keywords": [
+    "markdownlint-rule"
+  ],
+  "private": true
+}

test/rules/node_modules/markdownlint-rule-sample-module/sample-rule.mjs

@@ -0,0 +1,18 @@
+// @ts-check
+
+const rule = {
+  "names": [ "sample-rule-module" ],
+  "description": "Sample rule (module)",
+  "tags": [ "sample" ],
+  "function": (params, onError) => {
+    const hrTokens = params.tokens.filter((token) => token.type === "hr");
+    for (const token of hrTokens) {
+      onError({
+        "lineNumber": token.lineNumber,
+        "detail": "Sample error for hr"
+      });
+    }
+  }
+};
+
+export default rule;