Add ESLint support

Author: dandv

.eslintrc.cjs

@@ -0,0 +1,17 @@
+module.exports = {
+  parser: '@typescript-eslint/parser',
+  parserOptions: {
+    ecmaVersion: 2019,
+    sourceType: 'module',
+  },
+  plugins: [
+    '@typescript-eslint',
+  ],
+  env: {
+    node: true,  // for `console`
+  },
+  extends: [
+    'eslint:recommended',
+    'plugin:@typescript-eslint/recommended',
+  ],
+};

README.md

@@ -35,12 +35,18 @@ const influx = new Influx.InfluxDB();
 
 # Import your own modules without specifying an extension
 
-Run Node with the `node --experimental-specifier-resolution=node` parameter:
+When transpiling, [TypeScript won't generate an extension for you](https://github.com/microsoft/TypeScript/issues/16577). Run Node with the `node --experimental-specifier-resolution=node` parameter:
 
     node --experimental-specifier-resolution=node run.js
 
 Otherwise, [node mandates that you specify the extension](https://nodejs.org/api/esm.html#esm_mandatory_file_extensions) in the `import` statement.
 
 # Run the resulting JavaScript code
 
-Add `"type": "module"` to `package.json`, because [TypeScript can't generate files with the .mjs extension](https://github.com/microsoft/TypeScript/issues/18442#issuecomment-581738714).
+Add `"type": "module"` to `package.json`, because [TypeScript can't generate files with the .mjs extension](https://github.com/microsoft/TypeScript/issues/18442#issuecomment-581738714).
+
+# ESLint
+
+To be able to run `eslint`, we must create an `.eslintrc.cjs` file, rather than a `.js` one. Then, install the required dependencies:
+
+    npm i -D eslint @typescript-eslint/eslint-plugin @typescript-eslint/parser