Convert codebase to TS and update build tooling

.babelrc.js

@@ -0,0 +1,19 @@
+const { NODE_ENV, BABEL_ENV } = process.env
+const cjs = NODE_ENV === 'test' || BABEL_ENV === 'commonjs'
+
+module.exports = {
+  presets: [
+    [
+      '@babel/preset-env',
+      {
+        targets: {
+          ie: 11
+        },
+        loose: true,
+        modules: cjs ? 'cjs' : false
+      }
+    ],
+    '@babel/preset-typescript'
+  ],
+  plugins: [cjs && ['@babel/transform-modules-commonjs']].filter(Boolean)
+}

.eslintrc

@@ -1,6 +1,5 @@
 {
   "extends": [
-    "eslint-config-airbnb",
     "prettier",
     "plugin:@typescript-eslint/recommended"
   ],
@@ -21,6 +20,12 @@
     "no-use-before-define": [2, "nofunc"],
     "no-unused-expressions": 0,
     "import/no-unresolved": 0,
-    "import/named": 0
+    "import/named": 0,
+    "@typescript-eslint/ban-ts-ignore": 0,
+    "@typescript-eslint/explicit-function-return-type": 0,
+    "@typescript-eslint/no-explicit-any": 0,
+    "@typescript-eslint/member-delimiter-style": 0,
+    "@typescript-eslint/no-use-before-define": 1,
+    "@typescript-eslint/camelcase": 0
   }
 }

.gitignore

@@ -4,3 +4,4 @@ coverage
 lib
 dist
 es
+builds/

.prettierrc.json

@@ -0,0 +1,7 @@
+{
+  "semi": false,
+  "singleQuote": true,
+  "tabWidth": 2,
+  "trailingComma": "none",
+  "arrowParens": "avoid"
+}

jest.config.js

@@ -0,0 +1,14 @@
+/** @type {import('@ts-jest/dist/types').InitialOptionsTsJest} */
+
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+  coverageDirectory: './coverage/',
+  collectCoverage: true,
+  testRegex: 'test/test.ts',
+  globals: {
+    'ts-jest': {
+      tsconfig: './test/tsconfig.json',
+    },
+  },
+};