chore: add eslint back

.vscode/settings.json

@@ -0,0 +1,7 @@
+{
+  "editor.formatOnSave": true,
+  "editor.codeActionsOnSave": {
+    "source.fixAll.eslint": "explicit"
+  },
+  "eslint.validate": ["javascript"]
+}

demo/index.js

@@ -65,10 +65,12 @@ markers.on("click", (e) => {
   }
 });
 
+// eslint-disable-next-line no-unused-vars
 function addPoint() {
   worker.postMessage({ addPoint: true });
 }
 
+// eslint-disable-next-line no-unused-vars
 function removePoint() {
   worker.postMessage({ removePoint: true });
 }

eslint.config.js

@@ -0,0 +1,101 @@
+import { defineConfig } from "eslint/config";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+import js from "@eslint/js";
+import { FlatCompat } from "@eslint/eslintrc";
+import globals from "globals";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+const compat = new FlatCompat({
+  baseDirectory: __dirname,
+  recommendedConfig: js.configs.recommended,
+  allConfig: js.configs.all,
+});
+
+export default defineConfig([
+  {
+    extends: compat.extends(
+      "eslint:recommended",
+      "plugin:prettier/recommended",
+    ),
+
+    languageOptions: {
+      globals: {
+        ...globals.browser,
+        ...globals.node,
+      },
+      ecmaVersion: "latest",
+      sourceType: "module",
+    },
+
+    rules: {
+      // possible problems
+      "array-callback-return": 2,
+      "no-await-in-loop": 2,
+      "no-constructor-return": 2,
+      "no-duplicate-imports": 2,
+      "no-promise-executor-return": 2,
+      "no-self-compare": 2,
+      "no-template-curly-in-string": 2,
+      "no-unmodified-loop-condition": 2,
+      "no-unreachable-loop": 2,
+      "no-use-before-define": [2, "nofunc"],
+      "require-atomic-updates": 2,
+
+      // suggestions
+      "accessor-pairs": 2,
+      "arrow-body-style": 2,
+      "consistent-return": 2,
+      "dot-notation": 2,
+      eqeqeq: [2, "smart"],
+      "func-name-matching": 2,
+      "grouped-accessor-pairs": 2,
+      "new-cap": 2,
+      "no-array-constructor": 2,
+      "no-caller": 2,
+      "no-else-return": 2,
+      "no-extend-native": 2,
+      "no-extra-bind": 2,
+      "no-extra-label": 2,
+      "no-invalid-this": 2,
+      "no-iterator": 2,
+      "no-labels": 2,
+      "no-lone-blocks": 2,
+      "no-lonely-if": 2,
+      "no-loop-func": 2,
+      "no-new": 2,
+      "no-new-wrappers": 2,
+      "no-object-constructor": 2,
+      "no-proto": 2,
+      "no-return-assign": 2,
+      "no-sequences": 2,
+      "no-throw-literal": 2,
+      "no-undef-init": 2,
+      "no-unneeded-ternary": 2,
+      "no-unused-expressions": 2,
+      "no-useless-call": 2,
+      "no-useless-computed-key": 2,
+      "no-useless-concat": 2,
+      "no-useless-constructor": 2,
+      "no-useless-escape": 2,
+      "no-useless-rename": 2,
+      "no-useless-return": 2,
+      "no-var": 2,
+      "no-void": 2,
+      "no-with": 2,
+      "object-shorthand": 2,
+      "prefer-arrow-callback": 2,
+      "prefer-const": 2,
+      "prefer-promise-reject-errors": 2,
+      "prefer-rest-params": 2,
+      "prefer-spread": 2,
+      "prefer-numeric-literals": 2,
+      "prefer-template": 2,
+      "prefer-regex-literals": 2,
+      "require-await": 2,
+      strict: 2,
+      yoda: 2,
+    },
+  },
+]);

index.js

@@ -68,10 +68,10 @@ export default class Supercluster {
     if (log) console.time(timerId);
 
     this.trees = new Array(maxZoom + 2);
-    this.clusterData = Array.from({ length: maxZoom + 2 }, () => new Array());
-    this.emptyIndices = Array.from({ length: maxZoom + 2 }, () => new Array());
+    this.clusterData = Array.from({ length: maxZoom + 2 }, () => []);
+    this.emptyIndices = Array.from({ length: maxZoom + 2 }, () => []);
     this.points = structuredClone(points);
-    this.emptyPointIndices = new Array();
+    this.emptyPointIndices = [];
     points.length = 0;
 
     // generate a cluster object for each point and index input points into a R-tree
@@ -320,10 +320,7 @@ export default class Supercluster {
     );
     this._removeNodeFromTree(maxZoom + 1, pointIdx);
 
-    const ancestorRemovals = Array.from(
-      { length: maxZoom + 2 },
-      () => new Array(),
-    );
+    const ancestorRemovals = Array.from({ length: maxZoom + 2 }, () => []);
     ancestorRemovals[maxZoom + 1].push(removedNode);
     this._removeAncestors(
       maxZoom,
@@ -534,7 +531,7 @@ export default class Supercluster {
 
   _recluster(firstClusteringZoom, childLayerElements, ancestorRemovals) {
     const { minZoom, maxZoom } = this.options;
-    ancestorRemovals ??= Array.from({ length: maxZoom + 2 }, () => new Array());
+    ancestorRemovals ??= Array.from({ length: maxZoom + 2 }, () => []);
 
     let contiguousChildIdxs = this._visitContiguous(
       firstClusteringZoom + 1,
@@ -659,7 +656,7 @@ export default class Supercluster {
   _removeParentsOfChildren(zoom, childNodes) {
     const stride = this.stride;
     const removedParentIds = new Set();
-    const removedParentNodes = new Array();
+    const removedParentNodes = [];
     const r = this._calculateRadius(zoom);
 
     for (const node of childNodes) {