Eslint rule updates (#673)

* Install unicorn

* Add rules

* Fix issues

* Install sonarjs

* Set up rules

* Fix issues

* Install eslint-plugin-import and fix import extensions

* Simplify permitted error names

7 files changed, 25 insertions, 27 deletions

diff --git a/ext/js/dom/document-util.js b/ext/js/dom/document-util.js
index 1ec699e6..a98bfe86 100644
--- a/ext/js/dom/document-util.js
+++ b/ext/js/dom/document-util.js
@@ -18,7 +18,9 @@
 
 /**
  * This class contains utility functions related to the HTML document.
+ * TODO : This class should be made non-static
  */
+// eslint-disable-next-line unicorn/no-static-only-class
 export class DocumentUtil {
     /** @type {?boolean} */
     static _cssZoomSupported = null;
@@ -460,7 +462,7 @@ export class DocumentUtil {
             if (typeof value !== 'string' || value.length === 0) {
                 return null;
             }
-            value = parseFloat(value);
+            value = Number.parseFloat(value);
         }
         return !Number.isNaN(value) ? value : null;
     }
diff --git a/ext/js/dom/dom-text-scanner.js b/ext/js/dom/dom-text-scanner.js
index f1dc3661..5b3ea564 100644
--- a/ext/js/dom/dom-text-scanner.js
+++ b/ext/js/dom/dom-text-scanner.js
@@ -488,8 +488,8 @@ export class DOMTextScanner {
     static isStyleVisible(style) {
         return !(
             style.visibility === 'hidden' ||
-            parseFloat(style.opacity) <= 0 ||
-            parseFloat(style.fontSize) <= 0 ||
+            Number.parseFloat(style.opacity) <= 0 ||
+            Number.parseFloat(style.fontSize) <= 0 ||
             (
                 !DOMTextScanner.isStyleSelectable(style) &&
                 (
diff --git a/ext/js/dom/panel-element.js b/ext/js/dom/panel-element.js
index 9c1289d7..0f2801e6 100644
--- a/ext/js/dom/panel-element.js
+++ b/ext/js/dom/panel-element.js
@@ -89,16 +89,14 @@ export class PanelElement extends EventDispatcher {
      * @param {(details: import('core').EventArgument<import('panel-element').Events, TName>) => void} callback
      */
     on(eventName, callback) {
-        if (eventName === 'visibilityChanged') {
-            if (this._mutationObserver === null) {
-                this._visible = this.isVisible();
-                this._mutationObserver = new MutationObserver(this._onMutation.bind(this));
-                this._mutationObserver.observe(this._node, {
-                    attributes: true,
-                    attributeFilter: ['hidden'],
-                    attributeOldValue: true
-                });
-            }
+        if (eventName === 'visibilityChanged' && this._mutationObserver === null) {
+            this._visible = this.isVisible();
+            this._mutationObserver = new MutationObserver(this._onMutation.bind(this));
+            this._mutationObserver.observe(this._node, {
+                attributes: true,
+                attributeFilter: ['hidden'],
+                attributeOldValue: true
+            });
         }
         super.on(eventName, callback);
     }
@@ -111,11 +109,9 @@ export class PanelElement extends EventDispatcher {
      */
     off(eventName, callback) {
         const result = super.off(eventName, callback);
-        if (eventName === 'visibilityChanged' && !this.hasListeners(eventName)) {
-            if (this._mutationObserver !== null) {
-                this._mutationObserver.disconnect();
-                this._mutationObserver = null;
-            }
+        if (eventName === 'visibilityChanged' && !this.hasListeners(eventName) && this._mutationObserver !== null) {
+            this._mutationObserver.disconnect();
+            this._mutationObserver = null;
         }
         return result;
     }
diff --git a/ext/js/dom/popup-menu.js b/ext/js/dom/popup-menu.js
index 8a8a19ba..28bcc309 100644
--- a/ext/js/dom/popup-menu.js
+++ b/ext/js/dom/popup-menu.js
@@ -219,8 +219,8 @@ export class PopupMenu extends EventDispatcher {
             (bottom - top) * ((-vertical + 1) * -0.5)
         );
 
-        x = Math.max(0.0, Math.min(containerNodeRect.width - menuRect.width, x));
-        y = Math.max(0.0, Math.min(containerNodeRect.height - menuRect.height, y));
+        x = Math.max(0, Math.min(containerNodeRect.width - menuRect.width, x));
+        y = Math.max(0, Math.min(containerNodeRect.height - menuRect.height, y));
 
         menu.style.left = `${x}px`;
         menu.style.top = `${y}px`;
diff --git a/ext/js/dom/scroll-element.js b/ext/js/dom/scroll-element.js
index 8005469b..7cd00f01 100644
--- a/ext/js/dom/scroll-element.js
+++ b/ext/js/dom/scroll-element.js
@@ -133,10 +133,10 @@ export class ScrollElement {
      */
     _easeInOutCubic(t) {
         if (t < 0.5) {
-            return (4.0 * t * t * t);
+            return (4 * t * t * t);
         } else {
-            t = 1.0 - t;
-            return 1.0 - (4.0 * t * t * t);
+            t = 1 - t;
+            return 1 - (4 * t * t * t);
         }
     }
 
diff --git a/ext/js/dom/selector-observer.js b/ext/js/dom/selector-observer.js
index 791ce627..86607130 100644
--- a/ext/js/dom/selector-observer.js
+++ b/ext/js/dom/selector-observer.js
@@ -170,7 +170,7 @@ export class SelectorObserver {
 
         if (
             this._onChildrenUpdated !== null &&
-            (addedNodes.length !== 0 || addedNodes.length !== 0)
+            (removedNodes.length > 0 || addedNodes.length > 0)
         ) {
             for (let node = /** @type {?Node} */ (target); node !== null; node = node.parentNode) {
                 const observer = this._elementMap.get(node);
diff --git a/ext/js/dom/text-source-generator.js b/ext/js/dom/text-source-generator.js
index a5529779..83c7271c 100644
--- a/ext/js/dom/text-source-generator.js
+++ b/ext/js/dom/text-source-generator.js
@@ -307,8 +307,8 @@ export class TextSourceGenerator {
         // Adjust size
         const imposterRect = imposter.getBoundingClientRect();
         if (imposterRect.width !== elementRect.width || imposterRect.height !== elementRect.height) {
-            const width = parseFloat(elementStyle.width) + (elementRect.width - imposterRect.width);
-            const height = parseFloat(elementStyle.height) + (elementRect.height - imposterRect.height);
+            const width = Number.parseFloat(elementStyle.width) + (elementRect.width - imposterRect.width);
+            const height = Number.parseFloat(elementStyle.height) + (elementRect.height - imposterRect.height);
             this._setImposterStyle(imposterStyle, 'width', `${width}px`);
             this._setImposterStyle(imposterStyle, 'height', `${height}px`);
         }
@@ -614,7 +614,7 @@ export class TextSourceGenerator {
         }
         const style = window.getComputedStyle(element);
         return (
-            parseFloat(style.opacity) <= 0 ||
+            Number.parseFloat(style.opacity) <= 0 ||
             style.visibility === 'hidden' ||
             (style.backgroundImage === 'none' && this._isColorTransparent(style.backgroundColor))
         );