Add ESLint. Fix linting errors.

src/.eslintrc.json

@@ -0,0 +1,30 @@
+{
+    "env": {
+        "browser": true,
+        "es6": true
+    },
+    "extends": [
+        "standard",
+        "plugin:@typescript-eslint/eslint-recommended",
+        "plugin:@typescript-eslint/recommended"
+    ],
+    "globals": {
+        "Atomics": "readonly",
+        "SharedArrayBuffer": "readonly"
+    },
+    "parser": "@typescript-eslint/parser",
+    "parserOptions": {
+        "ecmaVersion": 2018,
+        "sourceType": "module"
+    },
+    "plugins": [
+        "@typescript-eslint"
+    ],
+    "rules": {
+        "no-tabs": "off",
+        "space-before-function-paren": "off",
+        "semi": "off",
+        "eol-last": "off",
+        "indent": "off"
+    }
+}

src/content.ts

@@ -1,9 +1,8 @@
-import { TwitterHider } from "./hider";
-import { Preferences } from "./interfaces/preferences";
-
+import { TwitterHider } from './hider';
+import { Preferences } from './interfaces/preferences';
 
 class Background {
-	static async init() {
+	static async init(): Promise<void> {
 		if (await this.checkIfFirstStart()) {
 			await this.setup();
 		}
@@ -11,14 +10,14 @@ class Background {
 		this.listen();
 	}
 
-	static async listen() {
+	static async listen(): Promise<void> {
 		const preferences: Preferences = await this.getSavedPreferences();
 		const hider = new TwitterHider(preferences);
 
 		hider.init();
 	}
 
-	static setup() {
+	static setup(): Promise<void> {
 		const defaults = {
 			hideLikes: true,
 			hideRetweets: true,
@@ -48,6 +47,4 @@ class Background {
 	}
 }
 
-
-
 Background.init();

src/hider.ts

@@ -1,31 +1,35 @@
-import { Preferences } from "./interfaces/preferences";
+import { Preferences } from './interfaces/preferences';
 
 export class TwitterHider {
 	private preferences: Preferences;
-	
+
+	private readonly hideLikesToggleAttr = 'data-hidelikes';
+	private readonly hideRetweetsToggleAttr = 'data-hideretweets';
+	private readonly HideRepliesToggleAttr = 'data-hidereplies';
+
 	constructor(preferences: Preferences) {
 		this.preferences = preferences;
 	}
 
-	public init() {
+	public init(): void {
 		this.setLikesVisibility(this.preferences.hideLikes);
 		this.setRetweetsVisibility(this.preferences.hideRetweets);
 		this.setRepliesVisibility(this.preferences.hideReplies);
 	}
 
-	private setLikesVisibility(visiblity: boolean) {
-		this.setAttributeOrRemoveIfNull(document.body, "data-hidelikes", this.trueStringOrNull(visiblity));
+	private setLikesVisibility(visiblity: boolean): void {
+		this.setAttributeOrRemoveIfNull(document.body, this.hideLikesToggleAttr, this.trueStringOrNull(visiblity));
 	}
 
-	private setRetweetsVisibility(visiblity: boolean) {
-		this.setAttributeOrRemoveIfNull(document.body, "data-hideretweets", this.trueStringOrNull(visiblity));
+	private setRetweetsVisibility(visiblity: boolean): void {
+		this.setAttributeOrRemoveIfNull(document.body, this.hideRetweetsToggleAttr, this.trueStringOrNull(visiblity));
 	}
 
-	private setRepliesVisibility(visiblity: boolean) {
-		this.setAttributeOrRemoveIfNull(document.body, "data-hidereplies", this.trueStringOrNull(visiblity));
+	private setRepliesVisibility(visiblity: boolean): void {
+		this.setAttributeOrRemoveIfNull(document.body, this.HideRepliesToggleAttr, this.trueStringOrNull(visiblity));
 	}
 
-	private setAttributeOrRemoveIfNull(element: HTMLElement, attributeName: string, value: string) {
+	private setAttributeOrRemoveIfNull(element: HTMLElement, attributeName: string, value: string): void {
 		if (!value) {
 			element.removeAttribute(attributeName);
 			return;
@@ -34,7 +38,7 @@ export class TwitterHider {
 		element.setAttribute(attributeName, value);
 	}
 
-	private trueStringOrNull(value: boolean) {
-		return value ? "true" : null;
+	private trueStringOrNull(value: boolean): string {
+		return value ? 'true' : null;
 	}
 }

src/manifest.json

@@ -1,7 +1,7 @@
 {
 	"name": "Cuckoo for Twitter",
 	"description": "Hide Twitter like, retweet and reply counts.",
-	"version": "2.0.0",
+	"version": "2.1.0",
 	"manifest_version": 2,
 	"content_scripts": [
 		{

src/package.json

@@ -1,8 +1,16 @@
 {
   "devDependencies": {
+    "@typescript-eslint/eslint-plugin": "^2.27.0",
+    "@typescript-eslint/parser": "^2.27.0",
+    "cpx": "1.5.0",
     "cssnano": "^4.1.10",
-    "typescript": "^3.8.3",
-    "cpx": "1.5.0"
+    "eslint": "^6.8.0",
+    "eslint-config-standard": "^14.1.1",
+    "eslint-plugin-import": "^2.20.2",
+    "eslint-plugin-node": "^11.1.0",
+    "eslint-plugin-promise": "^4.2.1",
+    "eslint-plugin-standard": "^4.0.1",
+    "typescript": "^3.8.3"
   },
   "scripts": {
     "build": "cpx manifest.json ../build/ && parcel build content.ts hider.ts popup.html hider.css --no-source-maps -d ../build/"