test.js

const fs = require("fs");

const keywords = JSON.parse(fs.readFileSync("keywords.txt").toString());
const news = JSON.parse(fs.readFileSync("news.txt").toString());
console.time();

news.reduce((foundNews, aNews) => {
	const stack = keywords.reduce((stack, keyword) => {
		if (aNews["title"].includes(keyword["title"]) || aNews["lead"]?.includes(keyword["title"]))
			stack.push(keyword["title"]);
		return stack;
	}, []);
	
	if (stack.length) {
		foundNews.push([aNews["id"], stack]);
	}
	
	return foundNews
}, [])

console.timeEnd();