build: add linter to make code style closer to Node.js' (#15)

.eslintrc

@@ -0,0 +1,9 @@
+{
+  "extends": ["plugin:eslint-plugin-node-core/recommended"],
+  "env": {
+    "node": true
+  },
+  "rules": {
+    "linebreak-style": 0
+  }
+}

index.js

@@ -5,83 +5,101 @@ const parseArgs = (
   options = {}
 ) => {
   if (typeof options !== 'object' || options === null) {
-    throw new Error('Whoops!')
+    throw new Error('Whoops!');
   }
   if (options.withValue !== undefined && !Array.isArray(options.withValue)) {
-    throw new Error('Whoops! options.withValue should be an array.')
+    throw new Error('Whoops! options.withValue should be an array.');
   }
 
-  let result = {
+  const result = {
     args: {},
     values: {},
     positionals: []
-  }
+  };
 
-  let pos = 0
+  let pos = 0;
   while (pos < argv.length) {
-    let arg = argv[pos]
+    let arg = argv[pos];
 
     if (arg.startsWith('-')) {
       // Everything after a bare '--' is considered a positional argument
       // and is returned verbatim
       if (arg === '--') {
-        result.positionals.push(...argv.slice(++pos))
-        return result
-      }
-      // look for shortcodes: -fXzy
-      else if (arg.charAt(1) !== '-') {
-        throw new Error('What are we doing with shortcodes!?!')
+        result.positionals.push(...argv.slice(++pos));
+        return result;
+      } else if (arg.charAt(1) !== '-') { // Look for shortcodes: -fXzy
+        throw new Error('What are we doing with shortcodes!?!');
       }
 
       // Any number of leading dashes are allowed
       // remove all leading dashes
-      arg = arg.replace(/^-+/, '')
+      arg = arg.replace(/^-+/, '');
 
       if (arg.includes('=')) {
-        //withValue equals(=) case
-        const argParts = arg.split('=')
+        // withValue equals(=) case
+        const argParts = arg.split('=');
 
-        result.args[argParts[0]] = true
-        //If withValue option is specified, take 2nd part after '=' as value, else set value as undefined
-        const val = options.withValue && options.withValue.includes(argParts[0]) ? argParts[1] : undefined
-        //Append value to previous arg values array for case of multiples option, else add to empty array
+        result.args[argParts[0]] = true;
+        // If withValue option is specified, take 2nd part after '=' as value,
+        // else set value as undefined
+        const val = options.withValue &&
+          options.withValue.includes(argParts[0]) ?
+          argParts[1] : undefined;
+        // Append value to previous arg values array for case of multiples
+        // option, else add to empty array
         result.values[argParts[0]] = [].concat(
-          options.multiples && options.multiples.includes(argParts[0]) && result.values[argParts[0]] || [],
+          options.multiples &&
+            options.multiples.includes(argParts[0]) &&
+            result.values[argParts[0]] || [],
           val,
-        )
-      } else if (pos + 1 < argv.length && !argv[pos+1].startsWith('-')) {
-        //withValue option should also support setting values when '=' isn't used
-        //ie. both --foo=b and --foo b should work
+        );
+      } else if (pos + 1 < argv.length && !argv[pos + 1].startsWith('-')) {
+        // withValue option should also support setting values when '=
+        // isn't used ie. both --foo=b and --foo b should work
 
-        result.args[arg] = true
-        //If withValue option is specified, take next position arguement as value and then increment pos so that we don't re-evaluate that arg, else set value as undefined
-        //ie. --foo b --bar c, after setting b as the value for foo, evaluate --bar next and skip 'b'
-        const val = options.withValue && options.withValue.includes(arg) ? argv[++pos] : undefined
-        //Append value to previous arg values array for case of multiples option, else add to empty array
+        result.args[arg] = true;
+        // If withValue option is specified, take next position arguement as
+        // value and then increment pos so that we don't re-evaluate that
+        // arg, else set value as undefined ie. --foo b --bar c, after setting
+        // b as the value for foo, evaluate --bar next and skip 'b'
+        const val = options.withValue && options.withValue.includes(arg) ?
+          argv[++pos] :
+          undefined;
+        // Append value to previous arg values array for case of multiples
+        // option, else add to empty array
         result.values[arg] = [].concat(
-          options.multiples && options.multiples.includes(arg) && result.values[arg] ? result.values[arg] : [],
-          val)
+          options.multiples && options.multiples.includes(arg) &&
+            result.values[arg] ?
+            result.values[arg] :
+            [],
+          val);
       } else {
-        //cases when an arg is specified without a value, example '--foo --bar' <- 'foo' and 'bar' args should be set to true and have value as undefined
-        result.args[arg] = true
-        //Append undefined to previous arg values array for case of multiples option, else add to empty array
+        // Cases when an arg is specified without a value, example
+        // '--foo --bar' <- 'foo' and 'bar' args should be set to true and
+        // shave value as undefined
+        result.args[arg] = true;
+        // Append undefined to previous arg values array for case of
+        // multiples option, else add to empty array
         result.values[arg] = [].concat(
-          options.multiples && options.multiples.includes(arg) && result.values[arg] ? result.values[arg] : [],
+          options.multiples && options.multiples.includes(arg) &&
+            result.values[arg] ?
+            result.values[arg] :
+            [],
           undefined
-        )
+        );
       }
 
     } else {
-      //Arguements without a dash prefix are considered "positional"
-      result.positionals.push(arg)
+      // Arguements without a dash prefix are considered "positional"
+      result.positionals.push(arg);
     }
 
-    pos++
+    pos++;
   }
 
-  return result
-}
+  return result;
+};
 
 module.exports = {
   parseArgs
-}
+};