Generate the adblocker engine only once (by using built-in caching)

plugins/adblocker/blocker.js

@@ -0,0 +1,33 @@
+const { promises } = require("fs"); // used for caching
+const path = require("path");
+
+const { ElectronBlocker } = require("@cliqz/adblocker-electron");
+const { session } = require("electron");
+const fetch = require("node-fetch");
+
+const SOURCES = [
+	"https://raw.githubusercontent.com/kbinani/adblock-youtube-ads/master/signed.txt"
+];
+
+const loadAdBlockerEngine = (enableBlocking = false) =>
+	ElectronBlocker.fromLists(
+		fetch,
+		SOURCES,
+		{},
+		{
+			path: path.resolve(__dirname, "ad-blocker-engine.bin"),
+			read: promises.readFile,
+			write: promises.writeFile
+		}
+	)
+		.then(blocker => {
+			if (enableBlocking) {
+				blocker.enableBlockingInSession(session.defaultSession);
+			}
+		})
+		.catch(err => console.log("Error loading adBlocker engine", err));
+
+module.exports = { loadAdBlockerEngine };
+if (require.main === module) {
+	loadAdBlockerEngine(false); // Generate the engine without enabling it
+}