fix(ci): improved svelte/typescript linting

* We drop the patched v3.0.0 of `eslint-plugin-svelte3` in favor of
  built-in TypeScript support in [v3.1.0][]
* To make the TypeScript linting work we extend the ESLint configuration
  with the recommended rules from `@typescript-eslint/eslint-plugin`.
* In turn, the recommended rules require us to make some adjustments to
  files and rules.

[v3.1.0]: https://github.com/sveltejs/eslint-plugin-svelte3/blob/master/CHANGELOG.md#310

Signed-off-by: Thomas Scholtes <thomas@monadic.xyz>

.eslintrc.js

@@ -1,6 +1,3 @@
-const eslintSveltePreprocess = require("eslint-svelte3-preprocess");
-const svelteConfig = require("./svelte.config");
-
 module.exports = {
   env: {
     node: true,
@@ -13,7 +10,7 @@ module.exports = {
     ecmaVersion: 2019,
     sourceType: "module",
   },
-  extends: ["eslint:recommended"],
+  extends: ["eslint:recommended", "plugin:@typescript-eslint/recommended"],
   plugins: ["svelte3", "@typescript-eslint", "no-only-tests"],
   overrides: [
     {
@@ -43,7 +40,6 @@ module.exports = {
   rules: {
     // Disallow Unused Variables
     // https://eslint.org/docs/rules/no-unused-vars
-    "no-unused-vars": ["error", { argsIgnorePattern: "^_" }],
     "@typescript-eslint/no-unused-vars": ["error", { argsIgnorePattern: "^_" }],
     // require using arrow functions as callbacks
     // https://eslint.org/docs/rules/prefer-arrow-callback
@@ -65,8 +61,15 @@ module.exports = {
     "spaced-comment": ["warn", "always"],
     // Disallow focused tests
     "no-only-tests/no-only-tests": "error",
+
+    // We are ok with providing explict type annotations for additional
+    // clarity.
+    "@typescript-eslint/no-inferrable-types": "off",
+    // We are ok with empty functions. Often we need a no-op function
+    // as an argument.
+    "@typescript-eslint/no-empty-function": "off",
   },
   settings: {
-    "svelte3/preprocess": eslintSveltePreprocess(svelteConfig.preprocess),
+    "svelte3/typescript": true,
   },
 };

builder/notarize.js

@@ -1,3 +1,4 @@
+/* eslint-disable @typescript-eslint/no-var-requires */
 const { notarize } = require("electron-notarize");
 const appId = require("../package.json").build.appId;
 

native/index.js

@@ -1,2 +1,3 @@
+/* eslint-disable @typescript-eslint/no-var-requires */
 require("ts-node").register();
 require("./index.ts");

native/preload.js

@@ -1,3 +1,4 @@
+// eslint-disable-next-line @typescript-eslint/no-var-requires
 const { ipcRenderer, contextBridge } = require("electron");
 
 contextBridge.exposeInMainWorld("electron", {

package.json

@@ -99,8 +99,7 @@
     "eslint": "^7.25.0",
     "eslint-plugin-cypress": "^2.11.2",
     "eslint-plugin-no-only-tests": "^2.5.0",
-    "eslint-plugin-svelte3": "=3.0.0",
-    "eslint-svelte3-preprocess": "=0.0.4",
+    "eslint-plugin-svelte3": "^3.2.0",
     "exit-hook": "^2.2.1",
     "ganache-cli": "^6.12.2",
     "html-webpack-plugin": "^5.3.1",