chore: run tests on all supported versions of Node.js (#77)

* pin esmock dependency to v2.3

* patch esmock, don't pin version

* update comments

* run patch in `prepare` script

Author: fasttime

package.json

@@ -30,6 +30,7 @@
     },
     "scripts": {
         "lint": "eslint . --report-unused-disable-directives",
+        "prepare": "node tests/patch-esmock.js",
         "release:generate:latest": "eslint-generate-release",
         "release:generate:alpha": "eslint-generate-prerelease alpha",
         "release:generate:beta": "eslint-generate-prerelease beta",
@@ -58,7 +59,8 @@
         "eslint": "^8.48.0",
         "eslint-config-eslint": "^9.0.0",
         "eslint-release": "^3.2.0",
-        "esmock": "^2.2.3",
+        "esmock": "^2.5.8",
+        "esmock_legacy": "npm:esmock@~2.3.8",
         "espree": "^9.0.0",
         "globals": "^13.21.0",
         "lint-staged": "^12.1.2",

tests/patch-esmock.js

@@ -0,0 +1,22 @@
+/**
+ * @fileoverview Run by npm to replace esmock with a legacy release on older versions of Node.js.
+ * @author Francesco Trotta
+ */
+
+import { promises as fs } from "fs";
+
+// * esmock < 2.4 works only on Node.js < 19.
+// * esmock >= 2.4 works only on Node.js >= 18.6.
+// If we are running Node.js < 19, replace the esmock dependency with the legacy release.
+// 111 is the ABI version number of Node.js 19: https://nodejs.org/en/download/releases
+if (process.versions.modules < 111) {
+    (async () => {
+        try {
+            await fs.access("node_modules/esmock_legacy");
+        } catch {
+            return;
+        }
+        await fs.rmdir("node_modules/esmock", { recursive: true });
+        await fs.rename("node_modules/esmock_legacy", "node_modules/esmock");
+    })();
+}