Add Babel and ESLint configuration files

.babelrc

@@ -0,0 +1,3 @@
+{
+  "presets": ["@babel/preset-env"]
+}

.eslintignore

@@ -0,0 +1,2 @@
+node_modules/
+dist/

.eslintrc.cjs

@@ -0,0 +1,19 @@
+module.exports = {
+  parser: '@babel/eslint-parser',
+  env: {
+    browser: true,
+    commonjs: true,
+    es2021: true,
+    node: true,
+    'jest/globals': true,
+  },
+  extends: [
+    'eslint:recommended',
+    'plugin:import/errors',
+    'plugin:import/warnings',
+  ],
+  plugins: ['jest'],
+  rules: {
+    // add your custom rules here
+  },
+};