refactor: add more rules to ESLint config, fix warnings (#3152)

vaadin · Dec 3, 2021 · e2b36f2 · e2b36f2
1 parent 191badc
commit e2b36f2
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Showing 45 changed files with 268 additions and 305 deletions.
diff --git a/.eslintrc.json b/.eslintrc.json
@@ -57,6 +57,7 @@
     "lines-between-class-members": ["error", "always", { "exceptAfterSingleLine": true }],
     "max-classes-per-file": ["error", 3],
     "max-params": ["error", 4],
+    "no-else-return": "error",
     "no-eval": "error",
     "no-implicit-coercion": ["error", { "allow": ["!!"] }],
     "no-promise-executor-return": "error",
@@ -66,7 +67,9 @@
     "no-sync": "off",
     "no-throw-literal": "error",
     "no-useless-return": "error",
+    "prefer-const": ["error", { "ignoreReadBeforeAssign": true }],
     "prefer-exponentiation-operator": "error",
+    "prefer-object-spread": "error",
     "prefer-rest-params": "error",
     "prefer-spread": "error",
     "space-in-parens": ["error", "never"],

diff --git a/packages/board/src/vaadin-board-row.js b/packages/board/src/vaadin-board-row.js
@@ -203,7 +203,7 @@ class BoardRow extends ElementMixin(mixinBehaviors([IronResizableBehavior], Poly
   _removeExtraNodesFromDOM(boardCols, nodes) {
     let isErrorReported = false;
     let spaceLeft = 4;
-    let returnNodes = [];
+    const returnNodes = [];
     nodes.forEach((node, i) => {
       spaceLeft = spaceLeft - boardCols[i];
       if (spaceLeft < 0) {
@@ -253,7 +253,7 @@ class BoardRow extends ElementMixin(mixinBehaviors([IronResizableBehavior], Poly
       const boardCols = this._parseBoardCols(filteredNodes);
       const colsInRow = boardCols.reduce((a, b) => a + b, 0);
       this._removeExtraNodesFromDOM(boardCols, filteredNodes).forEach((e, i) => {
-        let newFlexBasis = this._calculateFlexBasis(boardCols[i], width, colsInRow, breakpoints);
+        const newFlexBasis = this._calculateFlexBasis(boardCols[i], width, colsInRow, breakpoints);
         if (forceResize || !this._oldFlexBasis[i] || this._oldFlexBasis[i] != newFlexBasis) {
           this._oldFlexBasis[i] = newFlexBasis;
           e.style.flexBasis = newFlexBasis;

diff --git a/packages/charts/src/vaadin-chart-series.js b/packages/charts/src/vaadin-chart-series.js
@@ -371,7 +371,7 @@ class ChartSeries extends PolymerElement {
       if (parent && parent instanceof Chart) {
         if (unit && !parent.__getAxis(unit)) {
           const title = { title: { text: unit } };
-          parent.__addAxis(Object.assign({ id: unit, axisGenerated: true }, title));
+          parent.__addAxis({ id: unit, axisGenerated: true, ...title });
         }
         series.update({ yAxis: unit || 0 });
 

diff --git a/packages/charts/src/vaadin-chart.js b/packages/charts/src/vaadin-chart.js
@@ -526,7 +526,7 @@ class Chart extends ElementMixin(ThemableMixin(PolymerElement)) {
         return;
       }
 
-      const options = Object.assign({}, this.options, this._jsonConfigurationBuffer);
+      const options = { ...this.options, ...this._jsonConfigurationBuffer };
       this._jsonConfigurationBuffer = null;
       this.__initChart(options);
       this.__addChildObserver();
@@ -540,7 +540,7 @@ class Chart extends ElementMixin(ThemableMixin(PolymerElement)) {
    * @return {!Options}
    */
   get options() {
-    const options = Object.assign({}, this._baseConfig);
+    const options = { ...this._baseConfig };
     deepMerge(options, this.additionalOptions);
 
     if (this.type) {
@@ -635,7 +635,7 @@ class Chart extends ElementMixin(ThemableMixin(PolymerElement)) {
     if (this.chart3d) {
       options.chart = options.chart || {};
 
-      options.chart.options3d = Object.assign({}, this._baseChart3d, options.chart.options3d);
+      options.chart.options3d = { ...this._baseChart3d, ...options.chart.options3d };
     }
 
     return options;
@@ -1146,7 +1146,7 @@ class Chart extends ElementMixin(ThemableMixin(PolymerElement)) {
       }
 
       if (resetConfiguration) {
-        const initialOptions = Object.assign({}, this.options, this._jsonConfigurationBuffer);
+        const initialOptions = { ...this.options, ...this._jsonConfigurationBuffer };
 
         this.__initChart(initialOptions);
 
@@ -1610,12 +1610,11 @@ class Chart extends ElementMixin(ThemableMixin(PolymerElement)) {
     if (chart3d) {
       config.update({
         chart: {
-          options3d: Object.assign(
-            {},
-            this._baseChart3d,
-            this.additionalOptions && this.additionalOptions.chart && this.additionalOptions.chart.options3d,
-            { enabled: true }
-          )
+          options3d: {
+            ...this._baseChart3d,
+            ...(this.additionalOptions && this.additionalOptions.chart && this.additionalOptions.chart.options3d),
+            enabled: true
+          }
         }
       });
     } else {

diff --git a/packages/combo-box/src/vaadin-combo-box-data-provider-mixin.js b/packages/combo-box/src/vaadin-combo-box-data-provider-mixin.js
@@ -158,9 +158,8 @@ export const ComboBoxDataProviderMixin = (superClass) =>
       const loadedItem = this.filteredItems[page * this.pageSize];
       if (loadedItem !== undefined) {
         return loadedItem instanceof ComboBoxPlaceholder;
-      } else {
-        return this.size === undefined;
       }
+      return this.size === undefined;
     }
 
     /** @private */

diff --git a/packages/combo-box/src/vaadin-combo-box-light.js b/packages/combo-box/src/vaadin-combo-box-light.js
@@ -133,9 +133,8 @@ class ComboBoxLight extends ComboBoxDataProviderMixin(ComboBoxMixin(ThemableMixi
   checkValidity() {
     if (this.inputElement.validate) {
       return this.inputElement.validate();
-    } else {
-      return super.checkValidity();
     }
+    return super.checkValidity();
   }
 
   /**

diff --git a/packages/combo-box/src/vaadin-combo-box-scroller.js b/packages/combo-box/src/vaadin-combo-box-scroller.js
@@ -221,9 +221,8 @@ export class ComboBoxScroller extends PolymerElement {
       return false;
     } else if (itemIdPath && item !== undefined && selectedItem !== undefined) {
       return this.get(itemIdPath, item) === this.get(itemIdPath, selectedItem);
-    } else {
-      return item === selectedItem;
     }
+    return item === selectedItem;
   }
 
   /** @private */

diff --git a/packages/combo-box/test/combo-box-light.test.js b/packages/combo-box/test/combo-box-light.test.js
@@ -294,7 +294,7 @@ describe('custom buttons', () => {
       const y = Math.ceil(rect.top);
       // Get the element which would be targeted, when the user
       // tries to click on this position
-      let target = elementFromPointDeep(x, y, elem.ownerDocument);
+      const target = elementFromPointDeep(x, y, elem.ownerDocument);
       if (!target) {
         return;
       }

diff --git a/packages/component-base/src/async.js b/packages/component-base/src/async.js
@@ -23,17 +23,17 @@
 // Microtask implemented using Mutation Observer
 let microtaskCurrHandle = 0;
 let microtaskLastHandle = 0;
-let microtaskCallbacks = [];
+const microtaskCallbacks = [];
 let microtaskNodeContent = 0;
 let microtaskScheduled = false;
-let microtaskNode = document.createTextNode('');
+const microtaskNode = document.createTextNode('');
 new window.MutationObserver(microtaskFlush).observe(microtaskNode, { characterData: true });
 
 function microtaskFlush() {
   microtaskScheduled = false;
   const len = microtaskCallbacks.length;
   for (let i = 0; i < len; i++) {
-    let cb = microtaskCallbacks[i];
+    const cb = microtaskCallbacks[i];
     if (cb) {
       try {
         cb();

diff --git a/packages/component-base/src/focus-utils.js b/packages/component-base/src/focus-utils.js
@@ -217,7 +217,7 @@ export function isElementFocused(element) {
  * @return {HTMLElement[]}
  */
 export function getFocusableElements(element) {
-  let focusableElements = [];
+  const focusableElements = [];
   const needsSortByTabIndex = collectFocusableNodes(element, focusableElements);
   // If there is at least one element with tabindex > 0, we need to sort
   // the final array by tabindex.≈