From 6e94888aa3d4ef76b8d37974ada7ed71b2358e57 Mon Sep 17 00:00:00 2001
From: Saneef Ansari <hello@saneef.com>
Date: Fri, 26 Dec 2025 12:00:04 +0530
Subject: [PATCH 01/17] memoize the functions

---
 src/getCollectionNewestGitCommitDate.js | 13 ++++++-----
 src/getGitCommitDateFromPath.js         | 10 +++++----
 src/utils/memoize.js                    | 29 +++++++++++++++++++++++++
 3 files changed, 43 insertions(+), 9 deletions(-)
 create mode 100644 src/utils/memoize.js

diff --git a/src/getCollectionNewestGitCommitDate.js b/src/getCollectionNewestGitCommitDate.js
index 64db7c9..60fec8d 100644
--- a/src/getCollectionNewestGitCommitDate.js
+++ b/src/getCollectionNewestGitCommitDate.js
@@ -1,14 +1,15 @@
 // @ts-check
+
 const getGitCommitDateFromPath = require("./getGitCommitDateFromPath");
+const memoize = require("./utils/memoize");
 
 /**
  * Gets the collection's newest Git commit date.
  *
  * @param      {Array<object>}  collection  The collection
- *
- * @return     {Date}           The collection newest git commit date.
+ * @return     {Date | undefined}  The collection newest git commit date.
  */
-module.exports = function (collection) {
+function getCollectionNewestGitCommitDate(collection) {
   if (!collection || !collection.length) {
     return;
   }
@@ -18,9 +19,11 @@ module.exports = function (collection) {
     // Timestamps will be undefined for the paths not
     // yet commited to Git. So weeding them out.
     .filter((ts) => Boolean(ts))
-    .map((ts) => ts.getTime());
+    .map((ts) => /** @type Date */ (ts).getTime());
 
   if (timestamps.length) {
     return new Date(Math.max(...timestamps));
   }
-};
+}
+
+module.exports = memoize(getCollectionNewestGitCommitDate);
diff --git a/src/getGitCommitDateFromPath.js b/src/getGitCommitDateFromPath.js
index 0865abc..5d9ffa7 100644
--- a/src/getGitCommitDateFromPath.js
+++ b/src/getGitCommitDateFromPath.js
@@ -1,6 +1,7 @@
 // @ts-check
 const path = require("path");
 const spawn = require("cross-spawn");
+const memoize = require("./utils/memoize");
 
 /**
  * Gets the Git commit date from path.
@@ -9,10 +10,9 @@ const spawn = require("cross-spawn");
  * https://github.com/vuejs/vuepress/blob/master/packages/%40vuepress/plugin-last-updated/
  *
  * @param      {string}  filePath  The file path
- *
- * @return     {Date}  The git commit date if path is commited to Git.
+ * @return     {Date | undefined}  The git commit date if path is commited to Git.
  */
-module.exports = function (filePath) {
+function getGitCommitDateFromPath(filePath) {
   let output;
 
   try {
@@ -34,4 +34,6 @@ module.exports = function (filePath) {
       return new Date(ts);
     }
   }
-};
+}
+
+module.exports = memoize(getGitCommitDateFromPath);
diff --git a/src/utils/memoize.js b/src/utils/memoize.js
new file mode 100644
index 0000000..b7052cb
--- /dev/null
+++ b/src/utils/memoize.js
@@ -0,0 +1,29 @@
+/**
+ * Memoize function
+ *
+ * The code is adapted from MemoizeFunction() of Eleventy project
+ * See https://github.com/11ty/eleventy/blob/5a65b244235bfcb64ecf085bfc65a99a670e9df4/src/Util/MemoizeFunction.js
+ *
+ * @param      {Function}  fn The function to memoize
+ * @return     {Function}
+ */
+function memoize(fn) {
+  const cache = new Map();
+
+  return (...args) => {
+    if (args.filter(Boolean).length > 1) {
+      console.warn("memoize() only supports single argument functions");
+      return fn(...args);
+    }
+
+    const [cacheKey] = args;
+
+    if (!cache.has(cacheKey)) {
+      cache.set(cacheKey, fn(...args));
+    }
+
+    return cache.get(cacheKey);
+  };
+}
+
+module.exports = memoize;

From e22edb39443a5fd287fb586ce6090a9efcb9b2a4 Mon Sep 17 00:00:00 2001
From: Saneef Ansari <hello@saneef.com>
Date: Fri, 26 Dec 2025 12:58:36 +0530
Subject: [PATCH 02/17] ci: adds github workflow to run tests

---
 .github/workflows/ci.yml | 26 ++++++++++++++++++++++++++
 .travis.yml              | 16 ----------------
 2 files changed, 26 insertions(+), 16 deletions(-)
 create mode 100644 .github/workflows/ci.yml
 delete mode 100644 .travis.yml

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..4c334af
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,26 @@
+on:
+  push:
+    branches-ignore:
+      - "gh-pages"
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: ["ubuntu-latest", "macos-latest", "windows-latest"]
+        node: ["18", "22"]
+    name: Node.js ${{ matrix.node }} on ${{ matrix.os }}
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+      - name: Setup node
+        uses: actions/setup-node@v3
+        with:
+          node-version: ${{ matrix.node }}
+      - run: npm install
+      - run: npm run lint
+      - run: npm test
+env:
+  YARN_GPG: no
\ No newline at end of file
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 37b1386..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,16 +0,0 @@
-language: node_js
-
-node_js:
-  - 14
-  - 16
-
-os:
-  - linux
-  - osx
-  - windows
-
-before_script:
-  - npm install
-script:
-  - npm run lint
-  - npm run test

From 036b2808aeecc595a55df8b8c6c1e43be6b2d42e Mon Sep 17 00:00:00 2001
From: Saneef Ansari <hello@saneef.com>
Date: Fri, 26 Dec 2025 13:41:42 +0530
Subject: [PATCH 03/17] test: bumps rimraf to v5.0

---
 package.json                              | 4 ++--
 tests/getCollectionNewestGitCommitDate.js | 3 +--
 tests/getGitCommitDateFromPath.js         | 3 +--
 3 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/package.json b/package.json
index d37d908..13af87e 100644
--- a/package.json
+++ b/package.json
@@ -33,9 +33,9 @@
     "eslint-plugin-prettier": "^3.4.0",
     "husky": "^7.0.1",
     "lint-staged": "^11.1.2",
-    "nyc": "^15.1.0",
+    "nyc": "^17.1.0",
     "prettier": "^2.3.2",
-    "rimraf": "^3.0.2"
+    "rimraf": "^5.0.9"
   },
   "lint-staged": {
     "*.js": "eslint --cache --fix",
diff --git a/tests/getCollectionNewestGitCommitDate.js b/tests/getCollectionNewestGitCommitDate.js
index 7478f06..a0da2ea 100644
--- a/tests/getCollectionNewestGitCommitDate.js
+++ b/tests/getCollectionNewestGitCommitDate.js
@@ -1,8 +1,7 @@
 const test = require("ava");
 const path = require("path");
 const fs = require("fs/promises");
-const { promisify } = require("util");
-const rimraf = promisify(require("rimraf"));
+const { rimraf } = require("rimraf");
 const getCollectionNewestGitCommitDate = require("../src/getCollectionNewestGitCommitDate.js");
 
 const outputBase = path.join("tests/output/");
diff --git a/tests/getGitCommitDateFromPath.js b/tests/getGitCommitDateFromPath.js
index ca3314c..002c20a 100644
--- a/tests/getGitCommitDateFromPath.js
+++ b/tests/getGitCommitDateFromPath.js
@@ -1,8 +1,7 @@
 const test = require("ava");
 const path = require("path");
 const fs = require("fs/promises");
-const { promisify } = require("util");
-const rimraf = promisify(require("rimraf"));
+const { rimraf } = require("rimraf");
 const getGitCommitDateFromPath = require("../src/getGitCommitDateFromPath.js");
 
 const outputBase = path.join("tests/output/");

From e43b0b4fea6ee9c5cf414237cda1a3aa0fc82431 Mon Sep 17 00:00:00 2001
From: Saneef Ansari <hello@saneef.com>
Date: Fri, 26 Dec 2025 14:08:33 +0530
Subject: [PATCH 04/17] chore: bumps prettier and eslint

- Adds prettier-plugin-jsdoc
- Prettify JS files
---
 .eslintrc.js                            | 11 ---------
 eslint.config.js                        | 31 +++++++++++++++++++++++++
 package.json                            | 14 +++++++----
 prettier.config.js                      |  6 +++++
 src/getCollectionNewestGitCommitDate.js |  4 ++--
 src/getGitCommitDateFromPath.js         |  6 ++---
 src/utils/memoize.js                    |  8 +++----
 7 files changed, 55 insertions(+), 25 deletions(-)
 delete mode 100644 .eslintrc.js
 create mode 100644 eslint.config.js
 create mode 100644 prettier.config.js

diff --git a/.eslintrc.js b/.eslintrc.js
deleted file mode 100644
index 41b891e..0000000
--- a/.eslintrc.js
+++ /dev/null
@@ -1,11 +0,0 @@
-module.exports = {
-  root: true,
-  extends: ["xo-space", "plugin:prettier/recommended"],
-  plugins: ["prettier"],
-  rules: {
-    "prettier/prettier": "error",
-  },
-  env: {
-    browser: true,
-  },
-};
diff --git a/eslint.config.js b/eslint.config.js
new file mode 100644
index 0000000..a4c9fc8
--- /dev/null
+++ b/eslint.config.js
@@ -0,0 +1,31 @@
+const { defineConfig } = require("eslint/config");
+const prettier = require("eslint-plugin-prettier");
+const globals = require("globals");
+const js = require("@eslint/js");
+const { FlatCompat } = require("@eslint/eslintrc");
+
+const compat = new FlatCompat({
+  baseDirectory: __dirname,
+  recommendedConfig: js.configs.recommended,
+  allConfig: js.configs.all,
+});
+
+module.exports = defineConfig([
+  {
+    extends: compat.extends("xo-space", "plugin:prettier/recommended"),
+
+    plugins: {
+      prettier,
+    },
+
+    rules: {
+      "prettier/prettier": "error",
+    },
+
+    languageOptions: {
+      globals: {
+        ...globals.browser,
+      },
+    },
+  },
+]);
diff --git a/package.json b/package.json
index 13af87e..99ff780 100644
--- a/package.json
+++ b/package.json
@@ -26,15 +26,19 @@
     "cross-spawn": "^7.0.3"
   },
   "devDependencies": {
+    "@eslint/eslintrc": "^3.3.3",
+    "@eslint/js": "^9.39.2",
     "ava": "^3.15.0",
-    "eslint": "^7.32.0",
-    "eslint-config-prettier": "^8.3.0",
-    "eslint-config-xo-space": "^0.29.0",
-    "eslint-plugin-prettier": "^3.4.0",
+    "eslint": "^9.39.2",
+    "eslint-config-prettier": "^10.1.8",
+    "eslint-config-xo-space": "^0.35.0",
+    "eslint-plugin-prettier": "^5.5.4",
+    "globals": "^16.5.0",
     "husky": "^7.0.1",
     "lint-staged": "^11.1.2",
     "nyc": "^17.1.0",
-    "prettier": "^2.3.2",
+    "prettier": "^3.7.4",
+    "prettier-plugin-jsdoc": "^1.8.0",
     "rimraf": "^5.0.9"
   },
   "lint-staged": {
diff --git a/prettier.config.js b/prettier.config.js
new file mode 100644
index 0000000..84e8ce6
--- /dev/null
+++ b/prettier.config.js
@@ -0,0 +1,6 @@
+/** @type {import("prettier").Config} */
+const config = {
+  plugins: ["prettier-plugin-jsdoc"],
+};
+
+module.exports = config;
diff --git a/src/getCollectionNewestGitCommitDate.js b/src/getCollectionNewestGitCommitDate.js
index 60fec8d..3ff42d8 100644
--- a/src/getCollectionNewestGitCommitDate.js
+++ b/src/getCollectionNewestGitCommitDate.js
@@ -6,8 +6,8 @@ const memoize = require("./utils/memoize");
 /**
  * Gets the collection's newest Git commit date.
  *
- * @param      {Array<object>}  collection  The collection
- * @return     {Date | undefined}  The collection newest git commit date.
+ * @param {object[]} collection The collection
+ * @returns {Date | undefined} The collection newest git commit date.
  */
 function getCollectionNewestGitCommitDate(collection) {
   if (!collection || !collection.length) {
diff --git a/src/getGitCommitDateFromPath.js b/src/getGitCommitDateFromPath.js
index 5d9ffa7..567b4fe 100644
--- a/src/getGitCommitDateFromPath.js
+++ b/src/getGitCommitDateFromPath.js
@@ -9,8 +9,8 @@ const memoize = require("./utils/memoize");
  * The code is based on @vuepress/plugin-last-updated,
  * https://github.com/vuejs/vuepress/blob/master/packages/%40vuepress/plugin-last-updated/
  *
- * @param      {string}  filePath  The file path
- * @return     {Date | undefined}  The git commit date if path is commited to Git.
+ * @param {string} filePath The file path
+ * @returns {Date | undefined} The git commit date if path is commited to Git.
  */
 function getGitCommitDateFromPath(filePath) {
   let output;
@@ -19,7 +19,7 @@ function getGitCommitDateFromPath(filePath) {
     output = spawn.sync(
       "git",
       ["log", "-1", "--format=%at", path.basename(filePath)],
-      { cwd: path.dirname(filePath) }
+      { cwd: path.dirname(filePath) },
     );
   } catch {
     throw new Error("Fail to run 'git log'");
diff --git a/src/utils/memoize.js b/src/utils/memoize.js
index b7052cb..7fc1add 100644
--- a/src/utils/memoize.js
+++ b/src/utils/memoize.js
@@ -1,11 +1,11 @@
 /**
  * Memoize function
  *
- * The code is adapted from MemoizeFunction() of Eleventy project
- * See https://github.com/11ty/eleventy/blob/5a65b244235bfcb64ecf085bfc65a99a670e9df4/src/Util/MemoizeFunction.js
+ * The code is adapted from MemoizeFunction() of Eleventy project See
+ * https://github.com/11ty/eleventy/blob/5a65b244235bfcb64ecf085bfc65a99a670e9df4/src/Util/MemoizeFunction.js
  *
- * @param      {Function}  fn The function to memoize
- * @return     {Function}
+ * @param {Function} fn The function to memoize
+ * @returns {Function}
  */
 function memoize(fn) {
   const cache = new Map();

From e39147d638816217e07f432f9aab2437bea6d9cb Mon Sep 17 00:00:00 2001
From: Saneef Ansari <hello@saneef.com>
Date: Fri, 26 Dec 2025 14:20:00 +0530
Subject: [PATCH 05/17] chore: bumps ava to v6

- Move out ava config from package.json to ava.config.cjs
---
 ava.config.cjs |  6 ++++++
 package.json   | 11 +----------
 2 files changed, 7 insertions(+), 10 deletions(-)
 create mode 100644 ava.config.cjs

diff --git a/ava.config.cjs b/ava.config.cjs
new file mode 100644
index 0000000..073ae68
--- /dev/null
+++ b/ava.config.cjs
@@ -0,0 +1,6 @@
+module.exports = {
+  files: ["tests/**/*", "!tests/utils.js"],
+  watchMode: {
+    ignoreChanges: ["tests/output/**"],
+  },
+};
\ No newline at end of file
diff --git a/package.json b/package.json
index 99ff780..6154ea6 100644
--- a/package.json
+++ b/package.json
@@ -28,7 +28,7 @@
   "devDependencies": {
     "@eslint/eslintrc": "^3.3.3",
     "@eslint/js": "^9.39.2",
-    "ava": "^3.15.0",
+    "ava": "^6.4.1",
     "eslint": "^9.39.2",
     "eslint-config-prettier": "^10.1.8",
     "eslint-config-xo-space": "^0.35.0",
@@ -44,14 +44,5 @@
   "lint-staged": {
     "*.js": "eslint --cache --fix",
     "*.{js,md,json}": "prettier --write"
-  },
-  "ava": {
-    "files": [
-      "tests/**/*",
-      "!tests/utils.js"
-    ],
-    "ignoredByWatcher": [
-      "tests/output/**"
-    ]
   }
 }

From c1ad76c6f3dfe25ebacf137ab35905a06d6f2f7c Mon Sep 17 00:00:00 2001
From: Saneef Ansari <hello@saneef.com>
Date: Fri, 26 Dec 2025 16:02:39 +0530
Subject: [PATCH 06/17] makes ESM module

---
 .eleventy.js                              | 18 ------------------
 ava.config.cjs => ava.config.js           |  4 ++--
 eslint.config.js                          | 18 ++++++++++++------
 index.js                                  | 16 ++++++++++++++++
 package.json                              |  3 ++-
 prettier.config.js                        |  2 +-
 src/getCollectionNewestGitCommitDate.js   |  7 +++----
 src/getGitCommitDateFromPath.js           |  8 ++++----
 src/utils/memoize.js                      |  4 +---
 tests/getCollectionNewestGitCommitDate.js | 18 ++++++++++--------
 tests/getGitCommitDateFromPath.js         | 23 +++++++++++++----------
 11 files changed, 64 insertions(+), 57 deletions(-)
 delete mode 100644 .eleventy.js
 rename ava.config.cjs => ava.config.js (83%)
 create mode 100644 index.js

diff --git a/.eleventy.js b/.eleventy.js
deleted file mode 100644
index 0195bc3..0000000
--- a/.eleventy.js
+++ /dev/null
@@ -1,18 +0,0 @@
-// @ts-check
-const getGitCommitDateFromPath = require("./src/getGitCommitDateFromPath");
-const getCollectionNewestGitCommitDate = require("./src/getCollectionNewestGitCommitDate");
-
-module.exports = function (eleventyConfig) {
-  eleventyConfig.addFilter(
-    "getGitCommitDateFromPath",
-    getGitCommitDateFromPath
-  );
-  eleventyConfig.addFilter(
-    "getCollectionNewestGitCommitDate",
-    getCollectionNewestGitCommitDate
-  );
-};
-
-module.exports.getGitCommitDateFromPath = getGitCommitDateFromPath;
-module.exports.getCollectionNewestGitCommitDate =
-  getCollectionNewestGitCommitDate;
diff --git a/ava.config.cjs b/ava.config.js
similarity index 83%
rename from ava.config.cjs
rename to ava.config.js
index 073ae68..d283bd1 100644
--- a/ava.config.cjs
+++ b/ava.config.js
@@ -1,6 +1,6 @@
-module.exports = {
+export default {
   files: ["tests/**/*", "!tests/utils.js"],
   watchMode: {
     ignoreChanges: ["tests/output/**"],
   },
-};
\ No newline at end of file
+};
diff --git a/eslint.config.js b/eslint.config.js
index a4c9fc8..50bd80a 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -1,8 +1,14 @@
-const { defineConfig } = require("eslint/config");
-const prettier = require("eslint-plugin-prettier");
-const globals = require("globals");
-const js = require("@eslint/js");
-const { FlatCompat } = require("@eslint/eslintrc");
+import { FlatCompat } from "@eslint/eslintrc";
+import js from "@eslint/js";
+import prettier from "eslint-plugin-prettier";
+import { defineConfig } from "eslint/config";
+import globals from "globals";
+import path from "path";
+import { fileURLToPath } from "url";
+
+// Mimic CommonJS variables -- not needed if using CommonJS
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
 
 const compat = new FlatCompat({
   baseDirectory: __dirname,
@@ -10,7 +16,7 @@ const compat = new FlatCompat({
   allConfig: js.configs.all,
 });
 
-module.exports = defineConfig([
+export default defineConfig([
   {
     extends: compat.extends("xo-space", "plugin:prettier/recommended"),
 
diff --git a/index.js b/index.js
new file mode 100644
index 0000000..d8928e2
--- /dev/null
+++ b/index.js
@@ -0,0 +1,16 @@
+// @ts-check
+import getCollectionNewestGitCommitDate from "./src/getCollectionNewestGitCommitDate.js";
+import getGitCommitDateFromPath from "./src/getGitCommitDateFromPath.js";
+
+export default function (eleventyConfig) {
+  eleventyConfig.addFilter(
+    "getGitCommitDateFromPath",
+    getGitCommitDateFromPath,
+  );
+  eleventyConfig.addFilter(
+    "getCollectionNewestGitCommitDate",
+    getCollectionNewestGitCommitDate,
+  );
+}
+
+export { getCollectionNewestGitCommitDate, getGitCommitDateFromPath };
diff --git a/package.json b/package.json
index 6154ea6..a312cae 100644
--- a/package.json
+++ b/package.json
@@ -2,7 +2,8 @@
   "name": "eleventy-plugin-git-commit-date",
   "version": "0.1.3",
   "description": "Eleventy plugin to get Git commit time of a file, or a Eleventy collection.",
-  "main": ".eleventy.js",
+  "main": "index.js",
+  "type": "module",
   "repository": {
     "type": "git",
     "url": "git+https://github.com:saneef/eleventy-plugin-git-commit-date.git"
diff --git a/prettier.config.js b/prettier.config.js
index 84e8ce6..da08129 100644
--- a/prettier.config.js
+++ b/prettier.config.js
@@ -3,4 +3,4 @@ const config = {
   plugins: ["prettier-plugin-jsdoc"],
 };
 
-module.exports = config;
+export default config;
diff --git a/src/getCollectionNewestGitCommitDate.js b/src/getCollectionNewestGitCommitDate.js
index 3ff42d8..5d63142 100644
--- a/src/getCollectionNewestGitCommitDate.js
+++ b/src/getCollectionNewestGitCommitDate.js
@@ -1,7 +1,6 @@
 // @ts-check
-
-const getGitCommitDateFromPath = require("./getGitCommitDateFromPath");
-const memoize = require("./utils/memoize");
+import getGitCommitDateFromPath from "./getGitCommitDateFromPath.js";
+import memoize from "./utils/memoize.js";
 
 /**
  * Gets the collection's newest Git commit date.
@@ -26,4 +25,4 @@ function getCollectionNewestGitCommitDate(collection) {
   }
 }
 
-module.exports = memoize(getCollectionNewestGitCommitDate);
+export default memoize(getCollectionNewestGitCommitDate);
diff --git a/src/getGitCommitDateFromPath.js b/src/getGitCommitDateFromPath.js
index 567b4fe..e3e36cd 100644
--- a/src/getGitCommitDateFromPath.js
+++ b/src/getGitCommitDateFromPath.js
@@ -1,7 +1,7 @@
 // @ts-check
-const path = require("path");
-const spawn = require("cross-spawn");
-const memoize = require("./utils/memoize");
+import spawn from "cross-spawn";
+import path from "node:path";
+import memoize from "./utils/memoize.js";
 
 /**
  * Gets the Git commit date from path.
@@ -36,4 +36,4 @@ function getGitCommitDateFromPath(filePath) {
   }
 }
 
-module.exports = memoize(getGitCommitDateFromPath);
+export default memoize(getGitCommitDateFromPath);
diff --git a/src/utils/memoize.js b/src/utils/memoize.js
index 7fc1add..0e2a6fa 100644
--- a/src/utils/memoize.js
+++ b/src/utils/memoize.js
@@ -7,7 +7,7 @@
  * @param {Function} fn The function to memoize
  * @returns {Function}
  */
-function memoize(fn) {
+export default function memoize(fn) {
   const cache = new Map();
 
   return (...args) => {
@@ -25,5 +25,3 @@ function memoize(fn) {
     return cache.get(cacheKey);
   };
 }
-
-module.exports = memoize;
diff --git a/tests/getCollectionNewestGitCommitDate.js b/tests/getCollectionNewestGitCommitDate.js
index a0da2ea..d80366b 100644
--- a/tests/getCollectionNewestGitCommitDate.js
+++ b/tests/getCollectionNewestGitCommitDate.js
@@ -1,10 +1,11 @@
-const test = require("ava");
-const path = require("path");
-const fs = require("fs/promises");
-const { rimraf } = require("rimraf");
-const getCollectionNewestGitCommitDate = require("../src/getCollectionNewestGitCommitDate.js");
+import test from "ava";
+import { mkdir, writeFile } from "node:fs/promises";
+import path from "node:path";
+import { rimraf } from "rimraf";
+import { fileURLToPath } from "url";
+import { getCollectionNewestGitCommitDate } from "../index.js";
 
-const outputBase = path.join("tests/output/");
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
 
 test("Get newest commit date of collection", (t) => {
   const collection = [
@@ -23,6 +24,7 @@ test("Shouldn't get commit date from an empty collection", async (t) => {
 });
 
 test("Shouldn't get commit date from collection of uncommited files", async (t) => {
+  const outputBase = path.join("tests/output/");
   const collection = [
     { inputPath: path.join(outputBase, "test-01.md") },
     { inputPath: path.join(outputBase, "test-02.md") },
@@ -30,8 +32,8 @@ test("Shouldn't get commit date from collection of uncommited files", async (t)
 
   await rimraf(outputBase);
 
-  await fs.mkdir(outputBase, { recursive: true });
-  await Promise.all(collection.map((p) => fs.writeFile(p.inputPath, "")));
+  await mkdir(outputBase, { recursive: true });
+  await Promise.all(collection.map((p) => writeFile(p.inputPath, "")));
 
   t.is(getCollectionNewestGitCommitDate(collection), undefined);
 
diff --git a/tests/getGitCommitDateFromPath.js b/tests/getGitCommitDateFromPath.js
index 002c20a..9c2e29a 100644
--- a/tests/getGitCommitDateFromPath.js
+++ b/tests/getGitCommitDateFromPath.js
@@ -1,11 +1,11 @@
-const test = require("ava");
-const path = require("path");
-const fs = require("fs/promises");
-const { rimraf } = require("rimraf");
-const getGitCommitDateFromPath = require("../src/getGitCommitDateFromPath.js");
+import test from "ava";
+import { mkdir, writeFile } from "node:fs/promises";
+import path from "node:path";
+import { rimraf } from "rimraf";
+import { fileURLToPath } from "url";
+import { getGitCommitDateFromPath } from "../index.js";
 
-const outputBase = path.join("tests/output/");
-const tempFileName = "test.md";
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
 
 test("Get commit date of a committed file", (t) => {
   const filePath = path.join(__dirname, "./fixtures/sample.md");
@@ -15,11 +15,14 @@ test("Get commit date of a committed file", (t) => {
 });
 
 test("Should not get commit date of a uncommitted file", async (t) => {
-  const filePath = path.join(outputBase, tempFileName);
+  const outputBase = path.join(__dirname, "/output/");
+  const filePath = path.join(outputBase, "test.md");
   await rimraf(outputBase);
 
-  await fs.mkdir(outputBase, { recursive: true });
-  await fs.writeFile(filePath, "");
+  await mkdir(outputBase, { recursive: true }, (err) => {
+    console.error(err);
+  });
+  await writeFile(filePath, "");
 
   t.is(getGitCommitDateFromPath(filePath), undefined);
 

From cc2e52c057ee419be76ed909f30da12e9fcc39ef Mon Sep 17 00:00:00 2001
From: Saneef Ansari <hello@saneef.com>
Date: Fri, 26 Dec 2025 16:28:01 +0530
Subject: [PATCH 07/17] replaces husky with lefthook

---
 .husky/.gitignore |  1 -
 .husky/pre-commit |  5 -----
 lefthook.yml      | 14 ++++++++++++++
 package.json      | 10 ++--------
 4 files changed, 16 insertions(+), 14 deletions(-)
 delete mode 100644 .husky/.gitignore
 delete mode 100755 .husky/pre-commit
 create mode 100644 lefthook.yml

diff --git a/.husky/.gitignore b/.husky/.gitignore
deleted file mode 100644
index 31354ec..0000000
--- a/.husky/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-_
diff --git a/.husky/pre-commit b/.husky/pre-commit
deleted file mode 100755
index 6a06103..0000000
--- a/.husky/pre-commit
+++ /dev/null
@@ -1,5 +0,0 @@
-#!/bin/sh
-. "$(dirname "$0")/_/husky.sh"
-
-npm test
-npx lint-staged
\ No newline at end of file
diff --git a/lefthook.yml b/lefthook.yml
new file mode 100644
index 0000000..d465849
--- /dev/null
+++ b/lefthook.yml
@@ -0,0 +1,14 @@
+pre-commit:
+  commands:
+    prettier:
+      glob: "*.{js,md,json}"
+      run: prettier --write {staged_files}
+      stage_fixed: true
+
+    eslint:
+      glob: "*.{js}"
+      run: eslint --fix {staged_files}
+      stage_fixed: true
+
+    tests:
+      run: npm test
\ No newline at end of file
diff --git a/package.json b/package.json
index a312cae..6eeb4b8 100644
--- a/package.json
+++ b/package.json
@@ -10,8 +10,7 @@
   },
   "scripts": {
     "lint": "eslint src/**.js tests/**.js",
-    "test": "nyc ava --timeout=1m -v --color",
-    "prepare": "husky install"
+    "test": "nyc ava --timeout=1m -v --color"
   },
   "keywords": [
     "last-updated",
@@ -35,15 +34,10 @@
     "eslint-config-xo-space": "^0.35.0",
     "eslint-plugin-prettier": "^5.5.4",
     "globals": "^16.5.0",
-    "husky": "^7.0.1",
-    "lint-staged": "^11.1.2",
+    "lefthook": "^2.0.13",
     "nyc": "^17.1.0",
     "prettier": "^3.7.4",
     "prettier-plugin-jsdoc": "^1.8.0",
     "rimraf": "^5.0.9"
-  },
-  "lint-staged": {
-    "*.js": "eslint --cache --fix",
-    "*.{js,md,json}": "prettier --write"
   }
 }

From c74a3bd18e8cc9b90d4d0088c79df22663e8a6cd Mon Sep 17 00:00:00 2001
From: Saneef Ansari <hello@saneef.com>
Date: Fri, 26 Dec 2025 16:40:49 +0530
Subject: [PATCH 08/17] updates npmignore

---
 .npmignore | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/.npmignore b/.npmignore
index c346e3e..f061151 100644
--- a/.npmignore
+++ b/.npmignore
@@ -1,9 +1,10 @@
 .editorconfig
 .eslintcache
-.eslintrc.js
+.eslint.config.js
 .github/
-.husky/pre-commit
 .nyc_output
 tests
-.travis.yml
-.gitattributes
\ No newline at end of file
+.gitattributes
+prettier.config.js
+lefthook.yml
+ava.config.js
\ No newline at end of file

From 7844e15ac43c0afef5d9ab8069f6f8762e8de8a8 Mon Sep 17 00:00:00 2001
From: Saneef Ansari <hello@saneef.com>
Date: Fri, 26 Dec 2025 16:41:40 +0530
Subject: [PATCH 09/17] chore: run tests only on js file changes

---
 lefthook.yml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lefthook.yml b/lefthook.yml
index d465849..1666115 100644
--- a/lefthook.yml
+++ b/lefthook.yml
@@ -11,4 +11,5 @@ pre-commit:
       stage_fixed: true
 
     tests:
+      glob: "*.{js}"
       run: npm test
\ No newline at end of file

From e159c5ec3a21b5d9c4d473e8527f775c53741355 Mon Sep 17 00:00:00 2001
From: Saneef Ansari <hello@saneef.com>
Date: Fri, 26 Dec 2025 16:43:05 +0530
Subject: [PATCH 10/17] removes nyc

---
 package.json | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/package.json b/package.json
index 6eeb4b8..2c305bd 100644
--- a/package.json
+++ b/package.json
@@ -9,8 +9,7 @@
     "url": "git+https://github.com:saneef/eleventy-plugin-git-commit-date.git"
   },
   "scripts": {
-    "lint": "eslint src/**.js tests/**.js",
-    "test": "nyc ava --timeout=1m -v --color"
+    "test": "ava"
   },
   "keywords": [
     "last-updated",
@@ -35,7 +34,6 @@
     "eslint-plugin-prettier": "^5.5.4",
     "globals": "^16.5.0",
     "lefthook": "^2.0.13",
-    "nyc": "^17.1.0",
     "prettier": "^3.7.4",
     "prettier-plugin-jsdoc": "^1.8.0",
     "rimraf": "^5.0.9"

From 68a0d16fd1808bd84b24f6d5576ce2e3f7b82b7e Mon Sep 17 00:00:00 2001
From: Saneef Ansari <hello@saneef.com>
Date: Fri, 26 Dec 2025 16:48:47 +0530
Subject: [PATCH 11/17] fix(lefthook): fails to run prettier and eslint

---
 lefthook.yml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lefthook.yml b/lefthook.yml
index 1666115..4b49612 100644
--- a/lefthook.yml
+++ b/lefthook.yml
@@ -2,14 +2,14 @@ pre-commit:
   commands:
     prettier:
       glob: "*.{js,md,json}"
-      run: prettier --write {staged_files}
+      run: npx prettier --write {staged_files}
       stage_fixed: true
 
     eslint:
       glob: "*.{js}"
-      run: eslint --fix {staged_files}
+      run: npx eslint --fix {staged_files}
       stage_fixed: true
 
     tests:
       glob: "*.{js}"
-      run: npm test
\ No newline at end of file
+      run: npm run test
\ No newline at end of file

From 874f21dfb0da5873d2e3a65d39704812d49da471 Mon Sep 17 00:00:00 2001
From: Saneef Ansari <hello@saneef.com>
Date: Fri, 26 Dec 2025 16:49:26 +0530
Subject: [PATCH 12/17] chore: enables type check on config files

---
 eslint.config.js   | 1 +
 prettier.config.js | 1 +
 2 files changed, 2 insertions(+)

diff --git a/eslint.config.js b/eslint.config.js
index 50bd80a..08269f2 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -1,3 +1,4 @@
+// @ts-check
 import { FlatCompat } from "@eslint/eslintrc";
 import js from "@eslint/js";
 import prettier from "eslint-plugin-prettier";
diff --git a/prettier.config.js b/prettier.config.js
index da08129..fb9800e 100644
--- a/prettier.config.js
+++ b/prettier.config.js
@@ -1,3 +1,4 @@
+// @ts-check
 /** @type {import("prettier").Config} */
 const config = {
   plugins: ["prettier-plugin-jsdoc"],

From b4d3c6d452c9323552e2e5aee80471541995841c Mon Sep 17 00:00:00 2001
From: Saneef Ansari <hello@saneef.com>
Date: Fri, 26 Dec 2025 17:27:49 +0530
Subject: [PATCH 13/17] feat: make the filters async

- Make you Eleventy builds much faster
---
 index.js                                  |  4 ++--
 src/getCollectionNewestGitCommitDate.js   | 20 +++++++++-------
 src/getGitCommitDateFromPath.js           | 29 ++++++++++-------------
 src/utils/spawn.js                        | 28 ++++++++++++++++++++++
 tests/getCollectionNewestGitCommitDate.js | 10 ++++----
 tests/getGitCommitDateFromPath.js         | 12 ++++------
 6 files changed, 64 insertions(+), 39 deletions(-)
 create mode 100644 src/utils/spawn.js

diff --git a/index.js b/index.js
index d8928e2..c8412a3 100644
--- a/index.js
+++ b/index.js
@@ -3,11 +3,11 @@ import getCollectionNewestGitCommitDate from "./src/getCollectionNewestGitCommit
 import getGitCommitDateFromPath from "./src/getGitCommitDateFromPath.js";
 
 export default function (eleventyConfig) {
-  eleventyConfig.addFilter(
+  eleventyConfig.addAsyncFilter(
     "getGitCommitDateFromPath",
     getGitCommitDateFromPath,
   );
-  eleventyConfig.addFilter(
+  eleventyConfig.addAsyncFilter(
     "getCollectionNewestGitCommitDate",
     getCollectionNewestGitCommitDate,
   );
diff --git a/src/getCollectionNewestGitCommitDate.js b/src/getCollectionNewestGitCommitDate.js
index 5d63142..fa0c940 100644
--- a/src/getCollectionNewestGitCommitDate.js
+++ b/src/getCollectionNewestGitCommitDate.js
@@ -5,23 +5,27 @@ import memoize from "./utils/memoize.js";
 /**
  * Gets the collection's newest Git commit date.
  *
- * @param {object[]} collection The collection
- * @returns {Date | undefined} The collection newest git commit date.
+ * @param {object[]} collection Collection
+ * @returns {Promise<Date | undefined>} Newest git commit date among the items
+ *   in the collection
  */
-function getCollectionNewestGitCommitDate(collection) {
+async function getCollectionNewestGitCommitDate(collection) {
   if (!collection || !collection.length) {
     return;
   }
 
-  const timestamps = collection
-    .map((item) => getGitCommitDateFromPath(item.inputPath))
+  const timestamps = await Promise.all(
+    collection.map((item) => getGitCommitDateFromPath(item.inputPath)),
+  );
+
+  const dates = timestamps
     // Timestamps will be undefined for the paths not
     // yet commited to Git. So weeding them out.
     .filter((ts) => Boolean(ts))
-    .map((ts) => /** @type Date */ (ts).getTime());
+    .map((ts) => ts.getTime());
 
-  if (timestamps.length) {
-    return new Date(Math.max(...timestamps));
+  if (dates.length) {
+    return new Date(Math.max(...dates));
   }
 }
 
diff --git a/src/getGitCommitDateFromPath.js b/src/getGitCommitDateFromPath.js
index e3e36cd..d83fef0 100644
--- a/src/getGitCommitDateFromPath.js
+++ b/src/getGitCommitDateFromPath.js
@@ -1,7 +1,6 @@
 // @ts-check
-import spawn from "cross-spawn";
-import path from "node:path";
 import memoize from "./utils/memoize.js";
+import { spawnAsync } from "./utils/spawn.js";
 
 /**
  * Gets the Git commit date from path.
@@ -10,29 +9,25 @@ import memoize from "./utils/memoize.js";
  * https://github.com/vuejs/vuepress/blob/master/packages/%40vuepress/plugin-last-updated/
  *
  * @param {string} filePath The file path
- * @returns {Date | undefined} The git commit date if path is commited to Git.
+ * @returns {Promise<Date | undefined>} Commit date if path is commited to Git,
+ *   otherwise `undefined`
  */
-function getGitCommitDateFromPath(filePath) {
+async function getGitCommitDateFromPath(filePath) {
   let output;
 
   try {
-    output = spawn.sync(
-      "git",
-      ["log", "-1", "--format=%at", path.basename(filePath)],
-      { cwd: path.dirname(filePath) },
-    );
-  } catch {
+    output = await spawnAsync("git", ["log", "-1", "--format=%at", filePath]);
+  } catch (e) {
+    console.log(e);
     throw new Error("Fail to run 'git log'");
   }
 
-  if (output && output.stdout) {
-    const ts = parseInt(output.stdout.toString("utf-8"), 10) * 1000;
+  const ts = parseInt(output, 10) * 1000;
 
-    // Paths not commited to Git returns empty timestamps, resulting in NaN.
-    // So, convert only valid timestamps.
-    if (!isNaN(ts)) {
-      return new Date(ts);
-    }
+  // Paths not commited to Git returns empty timestamps, resulting in NaN.
+  // So, convert only valid timestamps.
+  if (!isNaN(ts)) {
+    return new Date(ts);
   }
 }
 
diff --git a/src/utils/spawn.js b/src/utils/spawn.js
new file mode 100644
index 0000000..f4aa6cc
--- /dev/null
+++ b/src/utils/spawn.js
@@ -0,0 +1,28 @@
+import { spawn } from "node:child_process";
+
+export function spawnAsync(command, args, options) {
+  return new Promise((resolve, reject) => {
+    const cmd = spawn(command, args, options);
+    const res = [];
+    cmd.stdout.on("data", (data) => {
+      res.push(data.toString("utf8"));
+    });
+
+    const err = [];
+    cmd.stderr.on("data", (data) => {
+      err.push(data.toString("utf8"));
+    });
+
+    cmd.on("close", (code) => {
+      if (err.length > 0) {
+        reject(err.join("\n"));
+      } else if (code === 1) {
+        reject(
+          new Error("Internal error: process closed with error exit code."),
+        );
+      } else {
+        resolve(res.join("\n"));
+      }
+    });
+  });
+}
diff --git a/tests/getCollectionNewestGitCommitDate.js b/tests/getCollectionNewestGitCommitDate.js
index d80366b..d8c0469 100644
--- a/tests/getCollectionNewestGitCommitDate.js
+++ b/tests/getCollectionNewestGitCommitDate.js
@@ -7,12 +7,12 @@ import { getCollectionNewestGitCommitDate } from "../index.js";
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url));
 
-test("Get newest commit date of collection", (t) => {
+test("Get newest commit date of collection", async (t) => {
   const collection = [
     { inputPath: path.join(__dirname, "./fixtures/sample.md") },
     { inputPath: path.join(__dirname, "./fixtures/another-sample-file.md") },
   ];
-  const date = getCollectionNewestGitCommitDate(collection);
+  const date = await getCollectionNewestGitCommitDate(collection);
   t.truthy(date);
   t.is(date.toISOString(), "2021-08-19T09:57:47.000Z");
 });
@@ -20,11 +20,11 @@ test("Get newest commit date of collection", (t) => {
 test("Shouldn't get commit date from an empty collection", async (t) => {
   const collection = [];
 
-  t.is(getCollectionNewestGitCommitDate(collection), undefined);
+  t.is(await getCollectionNewestGitCommitDate(collection), undefined);
 });
 
 test("Shouldn't get commit date from collection of uncommited files", async (t) => {
-  const outputBase = path.join("tests/output/");
+  const outputBase = path.join(__dirname, "output/collection");
   const collection = [
     { inputPath: path.join(outputBase, "test-01.md") },
     { inputPath: path.join(outputBase, "test-02.md") },
@@ -35,7 +35,7 @@ test("Shouldn't get commit date from collection of uncommited files", async (t)
   await mkdir(outputBase, { recursive: true });
   await Promise.all(collection.map((p) => writeFile(p.inputPath, "")));
 
-  t.is(getCollectionNewestGitCommitDate(collection), undefined);
+  t.is(await getCollectionNewestGitCommitDate(collection), undefined);
 
   await rimraf(outputBase);
 });
diff --git a/tests/getGitCommitDateFromPath.js b/tests/getGitCommitDateFromPath.js
index 9c2e29a..4a0a1d7 100644
--- a/tests/getGitCommitDateFromPath.js
+++ b/tests/getGitCommitDateFromPath.js
@@ -7,24 +7,22 @@ import { getGitCommitDateFromPath } from "../index.js";
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url));
 
-test("Get commit date of a committed file", (t) => {
+test("Get commit date of a committed file", async (t) => {
   const filePath = path.join(__dirname, "./fixtures/sample.md");
-  const date = getGitCommitDateFromPath(filePath);
+  const date = await getGitCommitDateFromPath(filePath);
   t.truthy(date);
   t.is(date.toISOString(), "2021-08-19T09:57:47.000Z");
 });
 
 test("Should not get commit date of a uncommitted file", async (t) => {
-  const outputBase = path.join(__dirname, "/output/");
+  const outputBase = path.join(__dirname, "/output/single-file-path");
   const filePath = path.join(outputBase, "test.md");
   await rimraf(outputBase);
 
-  await mkdir(outputBase, { recursive: true }, (err) => {
-    console.error(err);
-  });
+  await mkdir(outputBase, { recursive: true });
   await writeFile(filePath, "");
 
-  t.is(getGitCommitDateFromPath(filePath), undefined);
+  t.is(await getGitCommitDateFromPath(filePath), undefined);
 
   await rimraf(outputBase);
 });

From 1545238efa8f232c20e75bd97a54828f280aad49 Mon Sep 17 00:00:00 2001
From: Saneef Ansari <hello@saneef.com>
Date: Fri, 26 Dec 2025 17:59:08 +0530
Subject: [PATCH 14/17] fix(package.json): adds back lint script

---
 package.json | 1 +
 1 file changed, 1 insertion(+)

diff --git a/package.json b/package.json
index 2c305bd..1f31175 100644
--- a/package.json
+++ b/package.json
@@ -9,6 +9,7 @@
     "url": "git+https://github.com:saneef/eleventy-plugin-git-commit-date.git"
   },
   "scripts": {
+    "lint": "eslint src/**.js tests/**.js",
     "test": "ava"
   },
   "keywords": [

From 9085dad52ddce18638153f915a13aa28a4d31eff Mon Sep 17 00:00:00 2001
From: Saneef Ansari <hello@saneef.com>
Date: Fri, 26 Dec 2025 18:58:49 +0530
Subject: [PATCH 15/17] fix(npmignore): wrong file name

---
 .npmignore | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.npmignore b/.npmignore
index f061151..8aeaba2 100644
--- a/.npmignore
+++ b/.npmignore
@@ -1,10 +1,10 @@
 .editorconfig
 .eslintcache
-.eslint.config.js
 .github/
 .nyc_output
-tests
 .gitattributes
+eslint.config.js
+tests
 prettier.config.js
 lefthook.yml
 ava.config.js
\ No newline at end of file

From 9f8e97c80812c94453ef25ac257b01582053992c Mon Sep 17 00:00:00 2001
From: Saneef Ansari <hello@saneef.com>
Date: Fri, 26 Dec 2025 19:02:51 +0530
Subject: [PATCH 16/17] chore(editorconfig): updates MD related settings

---
 .editorconfig | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.editorconfig b/.editorconfig
index 7e66cb8..6726639 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -8,5 +8,5 @@ insert_final_newline = false
 trim_trailing_whitespace = true
 charset = utf-8
 
-[*.js]
-insert_final_newline = true
+[*.{js,md}]
+insert_final_newline = true
\ No newline at end of file

From 18e368fc388d513c48f52c1d1f09035e40a28a28 Mon Sep 17 00:00:00 2001
From: Saneef Ansari <hello@saneef.com>
Date: Fri, 26 Dec 2025 19:03:39 +0530
Subject: [PATCH 17/17] docs(readme): updates examples to ESM

---
 README.md | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index ed5dd47..b69bf4a 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ This Eleventy plugin provides two [template filters](https://www.11ty.dev/docs/f
 
 🌏 This plugin is made primarily to populate `<updated>` fields in an RSS feed. Here is [a blog post on how to use this plugin](https://saneef.com/tutorials/fix-dates-on-eleventy-rss-feeds/) with [`eleventy-plugin-rss`](https://www.11ty.dev/docs/plugins/rss/).
 
-⚠️ Getting Git commit date is a bit slow (\~50ms for each path). So, use it sparingly. It's recommended to call this filter within a production flag.
+⚠️ Git commit date is a bit slow. So, it's recommended to call this filter within a production flag.
 
 ## Usage
 
@@ -22,13 +22,13 @@ npm install eleventy-plugin-git-commit-date
 ### 2. Add to Eleventy config
 
 ```js
-// .eleventy.js
+// eleventy.config.js
 
-const pluginGitCommitDate = require("eleventy-plugin-git-commit-date");
+import pluginGitCommitDate from "eleventy-plugin-git-commit-date";
 
-module.exports = function (eleventyConfig) {
+export default function (eleventyConfig) {
   eleventyConfig.addPlugin(pluginGitCommitDate);
-};
+}
 ```
 
 ### 3. Use in templates