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
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/.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/.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: ${{ matrix.node }}
+      - run: npm install
+      - run: npm run lint
+      - run: npm test
+env:
+  YARN_GPG: no
\ No newline at end of file
diff --git a/.husky/.gitignore b/.husky/.gitignore
deleted file mode 100644
index 31354ec..0000000
--- a/.husky/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-_
diff --git a/.husky/pre-commit b/.husky/pre-commit
deleted file mode 100755
index 6a06103..0000000
--- a/.husky/pre-commit
+++ /dev/null
@@ -1,5 +0,0 @@
-#!/bin/sh
-. "$(dirname "$0")/_/husky.sh"
-
-npm test
-npx lint-staged
\ No newline at end of file
diff --git a/.npmignore b/.npmignore
index c346e3e..8aeaba2 100644
--- a/.npmignore
+++ b/.npmignore
@@ -1,9 +1,10 @@
 .editorconfig
 .eslintcache
-.eslintrc.js
 .github/
-.husky/pre-commit
 .nyc_output
+.gitattributes
+eslint.config.js
 tests
-.travis.yml
-.gitattributes
\ No newline at end of file
+prettier.config.js
+lefthook.yml
+ava.config.js
\ 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
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
diff --git a/ava.config.js b/ava.config.js
new file mode 100644
index 0000000..d283bd1
--- /dev/null
+++ b/ava.config.js
@@ -0,0 +1,6 @@
+export default {
+  files: ["tests/**/*", "!tests/utils.js"],
+  watchMode: {
+    ignoreChanges: ["tests/output/**"],
+  },
+};
diff --git a/eslint.config.js b/eslint.config.js
new file mode 100644
index 0000000..08269f2
--- /dev/null
+++ b/eslint.config.js
@@ -0,0 +1,38 @@
+// @ts-check
+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,
+  recommendedConfig: js.configs.recommended,
+  allConfig: js.configs.all,
+});
+
+export default defineConfig([
+  {
+    extends: compat.extends("xo-space", "plugin:prettier/recommended"),
+
+    plugins: {
+      prettier,
+    },
+
+    rules: {
+      "prettier/prettier": "error",
+    },
+
+    languageOptions: {
+      globals: {
+        ...globals.browser,
+      },
+    },
+  },
+]);
diff --git a/index.js b/index.js
new file mode 100644
index 0000000..c8412a3
--- /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.addAsyncFilter(
+    "getGitCommitDateFromPath",
+    getGitCommitDateFromPath,
+  );
+  eleventyConfig.addAsyncFilter(
+    "getCollectionNewestGitCommitDate",
+    getCollectionNewestGitCommitDate,
+  );
+}
+
+export { getCollectionNewestGitCommitDate, getGitCommitDateFromPath };
diff --git a/lefthook.yml b/lefthook.yml
new file mode 100644
index 0000000..4b49612
--- /dev/null
+++ b/lefthook.yml
@@ -0,0 +1,15 @@
+pre-commit:
+  commands:
+    prettier:
+      glob: "*.{js,md,json}"
+      run: npx prettier --write {staged_files}
+      stage_fixed: true
+
+    eslint:
+      glob: "*.{js}"
+      run: npx eslint --fix {staged_files}
+      stage_fixed: true
+
+    tests:
+      glob: "*.{js}"
+      run: npm run test
\ No newline at end of file
diff --git a/package.json b/package.json
index d37d908..1f31175 100644
--- a/package.json
+++ b/package.json
@@ -2,15 +2,15 @@
   "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"
   },
   "scripts": {
     "lint": "eslint src/**.js tests/**.js",
-    "test": "nyc ava --timeout=1m -v --color",
-    "prepare": "husky install"
+    "test": "ava"
   },
   "keywords": [
     "last-updated",
@@ -26,28 +26,17 @@
     "cross-spawn": "^7.0.3"
   },
   "devDependencies": {
-    "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",
-    "husky": "^7.0.1",
-    "lint-staged": "^11.1.2",
-    "nyc": "^15.1.0",
-    "prettier": "^2.3.2",
-    "rimraf": "^3.0.2"
-  },
-  "lint-staged": {
-    "*.js": "eslint --cache --fix",
-    "*.{js,md,json}": "prettier --write"
-  },
-  "ava": {
-    "files": [
-      "tests/**/*",
-      "!tests/utils.js"
-    ],
-    "ignoredByWatcher": [
-      "tests/output/**"
-    ]
+    "@eslint/eslintrc": "^3.3.3",
+    "@eslint/js": "^9.39.2",
+    "ava": "^6.4.1",
+    "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",
+    "lefthook": "^2.0.13",
+    "prettier": "^3.7.4",
+    "prettier-plugin-jsdoc": "^1.8.0",
+    "rimraf": "^5.0.9"
   }
 }
diff --git a/prettier.config.js b/prettier.config.js
new file mode 100644
index 0000000..fb9800e
--- /dev/null
+++ b/prettier.config.js
@@ -0,0 +1,7 @@
+// @ts-check
+/** @type {import("prettier").Config} */
+const config = {
+  plugins: ["prettier-plugin-jsdoc"],
+};
+
+export default config;
diff --git a/src/getCollectionNewestGitCommitDate.js b/src/getCollectionNewestGitCommitDate.js
index 64db7c9..fa0c940 100644
--- a/src/getCollectionNewestGitCommitDate.js
+++ b/src/getCollectionNewestGitCommitDate.js
@@ -1,26 +1,32 @@
 // @ts-check
-const getGitCommitDateFromPath = require("./getGitCommitDateFromPath");
+import getGitCommitDateFromPath from "./getGitCommitDateFromPath.js";
+import memoize from "./utils/memoize.js";
 
 /**
  * Gets the collection's newest Git commit date.
  *
- * @param      {Array<object>}  collection  The collection
- *
- * @return     {Date}           The collection newest git commit date.
+ * @param {object[]} collection Collection
+ * @returns {Promise<Date | undefined>} Newest git commit date among the items
+ *   in the collection
  */
-module.exports = function (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) => ts.getTime());
 
-  if (timestamps.length) {
-    return new Date(Math.max(...timestamps));
+  if (dates.length) {
+    return new Date(Math.max(...dates));
   }
-};
+}
+
+export default memoize(getCollectionNewestGitCommitDate);
diff --git a/src/getGitCommitDateFromPath.js b/src/getGitCommitDateFromPath.js
index 0865abc..d83fef0 100644
--- a/src/getGitCommitDateFromPath.js
+++ b/src/getGitCommitDateFromPath.js
@@ -1,6 +1,6 @@
 // @ts-check
-const path = require("path");
-const spawn = require("cross-spawn");
+import memoize from "./utils/memoize.js";
+import { spawnAsync } from "./utils/spawn.js";
 
 /**
  * Gets the Git commit date from path.
@@ -8,30 +8,27 @@ const spawn = require("cross-spawn");
  * 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}  The git commit date if path is commited to Git.
+ * @param {string} filePath The file path
+ * @returns {Promise<Date | undefined>} Commit date if path is commited to Git,
+ *   otherwise `undefined`
  */
-module.exports = function (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);
   }
-};
+}
+
+export default memoize(getGitCommitDateFromPath);
diff --git a/src/utils/memoize.js b/src/utils/memoize.js
new file mode 100644
index 0000000..0e2a6fa
--- /dev/null
+++ b/src/utils/memoize.js
@@ -0,0 +1,27 @@
+/**
+ * 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
+ * @returns {Function}
+ */
+export default 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);
+  };
+}
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 7478f06..d8c0469 100644
--- a/tests/getCollectionNewestGitCommitDate.js
+++ b/tests/getCollectionNewestGitCommitDate.js
@@ -1,18 +1,18 @@
-const test = require("ava");
-const path = require("path");
-const fs = require("fs/promises");
-const { promisify } = require("util");
-const rimraf = promisify(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) => {
+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");
 });
@@ -20,10 +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(__dirname, "output/collection");
   const collection = [
     { inputPath: path.join(outputBase, "test-01.md") },
     { inputPath: path.join(outputBase, "test-02.md") },
@@ -31,10 +32,10 @@ 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);
+  t.is(await getCollectionNewestGitCommitDate(collection), undefined);
 
   await rimraf(outputBase);
 });
diff --git a/tests/getGitCommitDateFromPath.js b/tests/getGitCommitDateFromPath.js
index ca3314c..4a0a1d7 100644
--- a/tests/getGitCommitDateFromPath.js
+++ b/tests/getGitCommitDateFromPath.js
@@ -1,28 +1,28 @@
-const test = require("ava");
-const path = require("path");
-const fs = require("fs/promises");
-const { promisify } = require("util");
-const rimraf = promisify(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) => {
+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 filePath = path.join(outputBase, tempFileName);
+  const outputBase = path.join(__dirname, "/output/single-file-path");
+  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 });
+  await writeFile(filePath, "");
 
-  t.is(getGitCommitDateFromPath(filePath), undefined);
+  t.is(await getGitCommitDateFromPath(filePath), undefined);
 
   await rimraf(outputBase);
 });