diff --git a/build.js b/build.mjs
similarity index 82%
rename from build.js
rename to build.mjs
index 2e414b3..0001223 100644
--- a/build.js
+++ b/build.mjs
@@ -1,10 +1,12 @@
-const replace = require('replace-in-file');
-const crypto = require('crypto');
-const pkg = require('./package.json');
-const pkgLock = require('./package-lock.json');
+import {replaceInFile} from 'replace-in-file'
+import crypto from 'crypto';
+import { readFile } from 'fs/promises';
 
-simplifyVersion = version => version.replace(/^[=<>~^]/g, '');
-majorMinorVersion = version => version.split('.').slice(0, -1).join('.');
+const pkg = JSON.parse(await readFile(new URL('./package.json', import.meta.url)));
+const pkgLock = JSON.parse(await readFile(new URL('./package-lock.json', import.meta.url)));
+
+const simplifyVersion = version => version.replace(/^[=<>~^]/g, '');
+const majorMinorVersion = version => version.split('.').slice(0, -1).join('.');
 
 const urls = {
     'bootstrap_js': 'https://cdn.jsdelivr.net/npm/bootstrap@' + simplifyVersion(pkgLock.packages["node_modules/bootstrap"].version) + '/dist/js/bootstrap.bundle.min.js',
@@ -41,6 +43,6 @@ async function calculateSris(urls) {
         to: [majorMinorVersion(process.env.npm_package_version), process.env.INLINE_CSS, process.env.INLINE_JS, ...Object.values(urls), ...sris],
         countMatches: true,
     };
-})().then(options => replace(options)
+})().then(options => replaceInFile(options)
     .then(results => results.every(result => (! result.hasChanged || result.numReplacements !== options.from.length) && (() => { throw new Error('error during build: no replacements done in file ' + result.file) })()))
 );
\ No newline at end of file
diff --git a/package.json b/package.json
index 9b1af06..7e32ffa 100644
--- a/package.json
+++ b/package.json
@@ -2,6 +2,7 @@
   "name": "moneymoney-sankey",
   "description": "An extension for the great MoneyMoney app to export an interactive HTML Sankey Chart based on the transaction categories",
   "version": "1.2.0",
+  "private": true,
   "dependencies": {
     "bootstrap": "^5.3.2",
     "highcharts": "^11.4.3"
@@ -19,7 +20,7 @@
   "scripts": {
     "build:css": "cleancss src/*.css",
     "build:js": "tsc && terser --compress --mangle -- $npm_package_config_outputDir/*.js",
-    "build": "mkdir -p $npm_package_config_outputDir && cp src/SankeyChart.lua $npm_package_config_outputDir && INLINE_CSS=`npm run build:css --silent` INLINE_JS=`npm run build:js --silent` node ./build.js",
+    "build": "mkdir -p $npm_package_config_outputDir && cp src/SankeyChart.lua $npm_package_config_outputDir && INLINE_CSS=`npm run build:css --silent` INLINE_JS=`npm run build:js --silent` node ./build.mjs",
     "test": "npm-run-all test:*",
     "test:compile-validate": "lua ./src/SankeyChartTest.lua | html-validate --stdin",
     "test:placeholder": "grep -qE '{{ ([a-zA-Z_]+) }}' $npm_package_config_outputDir/*.lua && (echo 'error: placeholders have not been replaced in dist!' && exit 1) || exit 0"