Setup eslint and enforce rules

src/cli/directive/options/FlagOption.ts

@@ -1,4 +1,4 @@
-import {CLIOption} from "./CLIOption"
+import {CLIOption} from './CLIOption'
 
 /**
  * Non-positional, flag-based CLI option.
@@ -24,8 +24,10 @@ export class FlagOption<T> extends CLIOption<T> {
          * Description of the argument required by this flag.
          * If this is set, the flag will expect a positional argument to follow as a param.
          */
-        public readonly argumentDescription?: string
-    ) { super() }
+        public readonly argumentDescription?: string,
+    ) {
+        super()
+    }
 
     /**
      * Get the referential name for this option.
@@ -33,7 +35,7 @@ export class FlagOption<T> extends CLIOption<T> {
      * be found, the short flag (without the '-') is used.
      * @returns {string}
      */
-    getArgumentName() {
+    getArgumentName(): string {
         if ( this.longFlag ) {
             return this.longFlag.replace('--', '')
         } else if ( this.shortFlag ) {