Observe the settings

Instead of making Atom lookup the settings on each lint call, observe them
in the activation so this work isn't needlessly repeated.

Author: Arcanemagus

lib/main.js

@@ -2,26 +2,36 @@
 
 import * as helpers from 'atom-linter';
 import { extname } from 'path';
+// eslint-disable-next-line import/extensions, import/no-extraneous-dependencies
+import { CompositeDisposable } from 'atom';
 
 export default {
-  activate: () => {
+  activate() {
     require('atom-package-deps').install('linter-ruby');
+
+    this.subscriptions = new CompositeDisposable();
+    this.subscriptions.add(atom.config.observe('linter-ruby.rubyExecutablePath',
+      (value) => { this.executablePath = value; }));
+    this.subscriptions.add(atom.config.observe('linter-ruby.ignoredExtensions',
+      (value) => { this.ignoredExtensions = value; }));
+  },
+
+  deactivate() {
+    this.subscriptions.dispose();
   },
 
-  provideLinter: () => {
+  provideLinter() {
     const regex = /.+:(\d+):\s*(.+?)[,:]\s(.+)/;
     return {
       name: 'Ruby',
       grammarScopes: ['source.ruby', 'source.ruby.rails', 'source.ruby.rspec'],
       scope: 'file',
       lintOnFly: true,
       lint: async (activeEditor) => {
-        const command = atom.config.get('linter-ruby.rubyExecutablePath');
-        const ignored = atom.config.get('linter-ruby.ignoredExtensions');
         const filePath = activeEditor.getPath();
         const fileExtension = extname(filePath).substr(1);
 
-        if (ignored.includes(fileExtension)) {
+        if (this.ignoredExtensions.includes(fileExtension)) {
           return [];
         }
 
@@ -30,7 +40,7 @@ export default {
           stdin: activeEditor.getText(),
           stream: 'stderr',
         };
-        const output = await helpers.exec(command, execArgs, execOpts);
+        const output = await helpers.exec(this.executablePath, execArgs, execOpts);
         const toReturn = [];
         output.split(/\r?\n/).forEach((line) => {
           const matches = regex.exec(line);