diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 842fef5..b702ff6 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -7,10 +7,9 @@ jobs:
         strategy:
             matrix:
                 node-version:
-                - 18.x
                 - 20.x
                 - 22.x
-                - 23.x
+                - latest
         steps:
         - uses: actions/checkout@v4
         - uses: actions/setup-node@v4
diff --git a/lib/util/files/finder.js b/lib/util/files/finder.js
index 2cf86d9..97900be 100644
--- a/lib/util/files/finder.js
+++ b/lib/util/files/finder.js
@@ -1,59 +1,40 @@
-let { readdir, stat } = require("fs/promises");
-let path = require("path");
+let { readdir, stat } = require("node:fs/promises");
+let path = require("node:path");
 
 exports.FileFinder = class FileFinder {
-	constructor(directory, { skipDotfiles, filter = () => true } = {}) {
+	constructor(directory, { skipDotfiles, filter } = {}) {
 		this.directory = directory;
 		this.filter = filename => {
-			if(skipDotfiles && isDotfile(filename)) {
+			if(skipDotfiles && path.basename(filename).startsWith(".")) {
 				return false;
 			}
-			return filter(filename);
+			return filter === undefined ? true : filter(filename);
 		};
 	}
 
 	// returns a list of relative file paths within the respective directory
-	all() {
-		return tree(this.directory).
-			then(filenames => filenames.filter(this.filter));
+	async all() {
+		let filenames = await tree(this.directory);
+		return filenames.filter(this.filter);
 	}
 
 	// returns all file paths that match the filter function
-	match(filepaths) {
-		return filesWithinDirectory(this.directory, filepaths).
-			then(filepaths => filepaths.filter(this.filter));
+	async match(filepaths) {
+		return filepaths.map(filepath => path.relative(this.directory, filepath)).
+			filter(filename => !filename.startsWith("..")).
+			filter(this.filter);
 	}
 };
 
-function tree(filepath, referenceDir = filepath) {
-	return stat(filepath).
-		then(res => {
-			if(!res.isDirectory()) {
-				return [path.relative(referenceDir, filepath)];
-			}
-
-			return readdir(filepath).
-				then(entries => {
-					let res = Promise.all(entries.map(entry => {
-						return tree(path.join(filepath, entry), referenceDir);
-					}));
-					return res.then(flatten);
-				});
-		});
-}
-
-function filesWithinDirectory(directory, files) {
-	return new Promise(resolve => {
-		resolve(files.
-			map(filepath => path.relative(directory, filepath)).
-			filter(filename => !filename.startsWith("..")));
-	});
-}
-
-function isDotfile(filename) {
-	return path.basename(filename).startsWith(".");
-}
+async function tree(filepath, referenceDir = filepath) {
+	let res = await stat(filepath);
+	if(!res.isDirectory()) {
+		return [path.relative(referenceDir, filepath)];
+	}
 
-function flatten(arr) {
-	return [].concat.apply([], arr);
+	let entries = await readdir(filepath);
+	entries = await Promise.all(entries.map(entry => {
+		return tree(path.join(filepath, entry), referenceDir);
+	}));
+	return entries.flat();
 }
diff --git a/package.json b/package.json
index 48bd905..2bca3d0 100644
--- a/package.json
+++ b/package.json
@@ -25,7 +25,7 @@
 		"lint": "eslint --cache ./lib ./bin/* ./test ./test/bin/* && echo ✓"
 	},
 	"engines": {
-		"node": ">= 18"
+		"node": ">= 20"
 	},
 	"dependencies": {
 		"browserslist": "~4.24.4",