feat: Add ESM

package.json

@@ -13,6 +13,11 @@
     },
     "main": "lib/index.js",
     "types": "lib/index.d.ts",
+    "module": "lib/esm/index.js",
+    "exports": {
+        "require": "./lib/index.js",
+        "import": "./lib/esm/index.js"
+    },
     "files": [
         "lib/**/*"
     ],
@@ -26,7 +31,9 @@
         "format:es": "npm run lint:es -- --fix",
         "format:prettier": "npm run prettier -- --write",
         "prettier": "prettier '**/*.{ts,md,json,yml}'",
-        "build": "tsc",
+        "build": "npm run build:cjs && npm run build:esm",
+        "build:cjs": "tsc --sourceRoot https://raw.githubusercontent.com/fb55/nth-check/$(git rev-parse HEAD)/src/",
+        "build:esm": "npm run build:cjs -- --module esnext --target es2019 --outDir lib/esm && echo '{\"type\":\"module\"}' > lib/esm/package.json",
         "prepare": "npm run build"
     },
     "repository": {
@@ -46,6 +53,7 @@
         "boolbase": "^1.0.0"
     },
     "devDependencies": {
+        "@types/boolbase": "^1.0.1",
         "@types/jest": "^27.5.0",
         "@types/node": "^17.0.35",
         "@typescript-eslint/eslint-plugin": "^5.25.0",

tsconfig.json

@@ -1,32 +1,32 @@
 {
     "compilerOptions": {
         /* Basic Options */
-        "target": "es5" /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019' or 'ESNEXT'. */,
-        "module": "commonjs" /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */,
-        // "lib": [],                             /* Specify library files to be included in the compilation. */
-        "declaration": true /* Generates corresponding '.d.ts' file. */,
-        "declarationMap": true /* Generates a sourcemap for each corresponding '.d.ts' file. */,
-        // "sourceMap": true,                     /* Generates corresponding '.map' file. */
-        "outDir": "lib" /* Redirect output structure to the directory. */,
-        // "importHelpers": true,                 /* Import emit helpers from 'tslib'. */
+        "target": "es5",
+        "module": "commonjs",
+        "lib": ["ES2015.Core"],
+        "declaration": true,
+        "declarationMap": true,
+        "sourceMap": true,
+        "outDir": "lib",
 
         /* Strict Type-Checking Options */
-        "strict": true /* Enable all strict type-checking options. */,
+        "strict": true,
 
         /* Additional Checks */
-        "noUnusedLocals": true /* Report errors on unused locals. */,
-        "noUnusedParameters": true /* Report errors on unused parameters. */,
-        "noImplicitReturns": true /* Report error when not all code paths in function return a value. */,
-        "noFallthroughCasesInSwitch": true /* Report errors for fallthrough cases in switch statement. */,
+        "forceConsistentCasingInFileNames": true,
+        "importsNotUsedAsValues": "error",
+        "isolatedModules": true,
+        "noFallthroughCasesInSwitch": true,
+        "noImplicitOverride": true,
+        "noImplicitReturns": true,
+        "noPropertyAccessFromIndexSignature": true,
+        "noUnusedLocals": true,
+        "noUnusedParameters": true,
 
         /* Module Resolution Options */
-        "baseUrl": "./" /* Base directory to resolve non-absolute module names. */,
-        "esModuleInterop": true /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */,
-        "resolveJsonModule": true,
-
-        "paths": {
-            "*": ["src/declarations/*", "*"]
-        }
+        "esModuleInterop": true,
+        "moduleResolution": "node",
+        "resolveJsonModule": true
     },
     "include": ["src"],
     "exclude": [