select which country to load

.gitignore

@@ -1,5 +1,5 @@
 node_modules
-dist
 .vscode
 web-ext-artifacts
 .amo-upload-uuid
+dist

README.md

@@ -0,0 +1,30 @@
+
+# :dollar: Kobo Price
+
+Helps you find the lowest book price on kobo.com.
+
+![example](./img/example.gif)
+
+## Installation
+You can install this script in several ways:
+
+- [Firefox add-on](https://addons.mozilla.org/en-US/firefox/addon/kobo-price)
+- [Chrome extension](https://chromewebstore.google.com/detail/kobo-price/gjiadglcgiidfphjijgeellagidbkiah)
+- [Userscript](https://raw.githubusercontent.com/fotonmoton/koboprice/master/userscript/koboprice.user.js)
+
+## Usage
+On kobo.com, the book price for each country could be different. This script will fetch all book prices, convert them to USD at today's rate, sort them, and show to you as a list. Then you can change your billing address to the country whose price you like and proceed to checkout.
+
+- Go to the book/audiobook page you want to buy
+- wait a couple of minutes until all the prices are loaded (you should see the progress on the right side of the book page)
+- get the list of prices sorted and converted to USD
+
+## Build
+
+All artifacts are based on the `dist/index.js` bundle. To get it, run `npm run bundle`. To get the web extension archive, run `npm run build-ext`. To get the userscript, run `npm run build-userscript`.
+
+To get all the above:
+
+```sh
+npm install && npm build-all
+```

eslint.config.js

@@ -4,7 +4,7 @@ import globals from "globals";
 
 export default [
   {
-    ignores: ["dist"],
+    ignores: ["dist", "userscript"],
   },
   eslintPluginPrettierRecommended,
   js.configs.recommended,

lib/bookPriceFor.js

@@ -1,5 +1,5 @@
 import { bookUrl } from "./bookUrl";
-import { extractPriceFrom } from "./extractPriceFrom";
+import { extractPrice } from "./extractPrice";
 import { getRate } from "./rates";
 import { convertPrice } from "./convertPrice";
 import { cacheBookPrice, getBookPrice } from "./cache";
@@ -17,7 +17,7 @@ export const bookPriceFor = async (country) => {
     return fromCache;
   }
 
-  const countryPrice = await extractPriceFrom(url);
+  const countryPrice = await extractPrice(url);
 
   let convertedPrice;
 

lib/bookUrl.js

@@ -1,6 +1,9 @@
 export const bookUrl = (country) => {
   const urlPattern = /^https:\/\/www\.kobo\.com\/../;
   const newPath = `https://www.kobo.com/${country}`;
+  const url = window.location.href.replace(urlPattern, newPath);
 
-  return window.location.href.replace(urlPattern, newPath);
+  l("url for country", country, url);
+
+  return url;
 };

lib/cache.js

@@ -1,18 +1,37 @@
+import { COUNTRIES } from "./countries";
+
 const CACHE_PREFIX = "KOBOPRICE";
 
+const initCountries = () =>
+	COUNTRIES.reduce(
+		(acc, { countryCode }) => ({ ...acc, [countryCode]: true }),
+		{},
+	);
+
 export const initCache = () => {
-  if (!localStorage.getItem(CACHE_PREFIX)) {
+	if (!localStorage.getItem(CACHE_PREFIX)) {
-    setState({ books: {}, rates: null });
+		setState({
-  }
+			books: {},
+			rates: null,
+			countries: initCountries(),
+		});
+	}
 };
 export const getState = () => JSON.parse(localStorage.getItem(CACHE_PREFIX));
 export const setState = (s) =>
-  localStorage.setItem(CACHE_PREFIX, JSON.stringify(s));
+	localStorage.setItem(CACHE_PREFIX, JSON.stringify(s));
 export const getRates = () => getState().rates;
 export const cacheRates = (rates) => setState({ ...getState(), rates });
 export const getBookPrice = (url) => getState().books[url];
 export const cacheBookPrice = (price, url) => {
-  const state = getState();
+	const state = getState();
-  state.books[url] = price;
+	state.books[url] = price;
-  setState(state);
+	setState(state);
+};
+export const getSelectedCountries = () =>
+	getState().countries || initCountries();
+export const cacheSelectedCountries = (countries) => {
+	const state = getState();
+	state.countries = countries;
+	setState(state);
 };

lib/convertPrice.js

@@ -26,9 +26,14 @@ export const convertPrice = async (price, curr, rate) => {
       price = price.replace("S/.", "");
       break;
     }
+    case "try": {
+      price = price.replace(".", "").replace(",", ".");
+      break;
+    }
     case "clp":
     case "cop":
-    case "twd": {
+    case "twd":
+    case "mxn": {
       break;
     }
     default:

lib/extractPrice.js

@@ -0,0 +1,51 @@
+const timeout = (duration) => new Promise((r) => setTimeout(r, duration));
+
+const observePriceOnPage = (page) =>
+	new Promise((res, rej) => {
+		timeout(5000).then(() => rej("price not found"));
+
+		var observer = new MutationObserver(() => {
+			const price = page?.querySelector(
+				".primary-right-container .pricing-details .active-price span",
+			)?.textContent;
+
+			if (price) {
+				l("found price", price);
+				observer.disconnect();
+				res(price);
+			}
+		});
+
+		observer.observe(page, {
+			childList: true,
+			characterData: true,
+			subtree: true,
+		});
+	});
+
+export const extractPrice = async (url) => {
+	try {
+		l("going to", url);
+
+		const iframe = document.createElement("iframe");
+
+		iframe.src = url;
+
+		iframe.hidden = true;
+
+		document.body.append(iframe);
+
+		await new Promise((res) => (iframe.contentWindow.onload = res));
+
+		l("starting observing price on", url);
+
+		const price = await observePriceOnPage(iframe.contentDocument.body);
+
+		document.body.removeChild(iframe);
+
+		return price;
+	} catch (e) {
+		l("getPriceForCountry", e, url);
+		return "";
+	}
+};

lib/extractPriceFrom.js

@@ -1,52 +0,0 @@
-const timeout = (duration) => new Promise((r) => setTimeout(r, duration));
-
-const observePriceOnPage = (page) =>
-  new Promise((res, rej) => {
-    timeout(10000).then(() => rej("price not found"));
-
-    var observer = new MutationObserver(() => {
-      const price = page.querySelector(
-        ".primary-right-container .pricing-details .active-price span",
-      ).textContent;
-
-      if (price) {
-        l("found price", price);
-        observer.disconnect();
-        res(price);
-      }
-    });
-
-    observer.observe(page, {
-      attributes: true,
-      childList: true,
-      characterData: true,
-      subtree: true,
-    });
-  });
-
-export const extractPriceFrom = async (url) => {
-  try {
-    l("going to", url);
-
-    const iframe = document.createElement("iframe");
-
-    iframe.src = url;
-
-    iframe.hidden = true;
-
-    document.body.append(iframe);
-
-    await new Promise((res) => (iframe.contentWindow.onload = res));
-
-    l("starting observing price on", url);
-
-    const price = await observePriceOnPage(iframe.contentDocument.body, url);
-
-    document.body.removeChild(iframe);
-
-    return price;
-  } catch (e) {
-    l("getPriceForCountry", e, url);
-    return "";
-  }
-};

lib/index.js

@@ -1,104 +1,208 @@
+import { useSelectedCountries } from "./useCountries";
 import "./logger";
-import { COUNTRIES } from "./countries";
+import { createElement, h, render } from "preact";
+import { useCallback, useEffect, useRef, useState } from "preact/hooks";
+import { bookUrl } from "./bookUrl";
 import { initCache } from "./cache";
-import { bookPriceFor } from "./bookPriceFor";
+import { usePrices } from "./usePrices";
 
 /*
 TODO:
-- publish to stores
 - more durable source for rates
-- React for UI
-- More informative UI, show loading progress
-- clear stale cache
 - readme how to use and debug
-- configuration (purge cache, change base currency)
 */
 
 const createPricesContainer = () => {
-  const pricingActionContainer = document.querySelector(
+	const pricingActionContainers = document.querySelectorAll(".pricing-details");
-    ".primary-right-container",
-  );
 
-  const container = document.createElement("div");
+	l("all pricing containers", pricingActionContainers);
 
-  container.style.display = "flex";
+	let visible;
-  container.style.flexDirection = "column";
+	for (const node of pricingActionContainers) {
-  container.style.border = "1px solid black";
+		if (node.checkVisibility()) {
-  container.style.padding = "10px";
+			l("found visible pricing container", node);
+			visible = node;
+			break;
+		}
+	}
 
-  return pricingActionContainer.parentNode.insertBefore(
+	return visible.parentNode.insertBefore(
-    container,
+		document.createElement("div"),
-    pricingActionContainer,
+		visible,
-  );
+	);
 };
 
-const getPrices = async () => {
+const isInLibrary = () => document.querySelectorAll(".read-now").length;
-  const prices = [];
-  for (const country of COUNTRIES) {
-    // intentionally blocking execution
-    // to resolve sequentially.
-    // It should prevent DOS and triggering captcha
-    prices.push(await bookPriceFor(country));
-  }
 
-  return prices;
+const formatPrice = (countryPrice, convertedPrice, isSelected) => {
+	if (!isSelected) return "SKIP";
+
+	if (countryPrice == undefined) {
+		return "NOT LOADED";
+	}
+
+	if (convertedPrice) {
+		return `${countryPrice} => ${convertedPrice?.formatted}`;
+	}
+
+	return "NOT FOUND";
 };
 
-const sortPrices = (prices) =>
+const Price = ({ price, toggleCountry, isSelected }) => {
-  prices.sort(
+	const { convertedPrice, countryCode, countryPrice } = price;
-    (a, b) =>
+	const [isHovered, setHover] = useState(false);
-      (a?.convertedPrice?.intValue || Infinity) -
-      (b?.convertedPrice?.intValue || Infinity),
-  );
 
-const showPrices = (container, prices) => {
+	const hover = useCallback(() => setHover(true));
-  container.innerText = null;
+	const leave = useCallback(() => setHover(false));
-  prices.forEach((price) => {
+
-    const link = document.createElement("a");
+	const style = {
-    link.href = price.url;
+		display: "flex",
-    link.target = "_blank";
+		flexDirection: "row",
-    link.style.marginBottom = "5px";
+		justifyContent: "space-between",
-    link.style.display = "flex";
+		alignItems: "center",
-    link.style.justifyContent = "space-between";
+		backgroundColor: isHovered ? "#d7d7d7" : "",
-    const oldPrice = document.createElement("p");
+		padding: "0 10px",
-    oldPrice.innerText = `${price.countryCode.toUpperCase()}: ${price?.countryPrice || "NO PRICE"}`;
+	};
-    const newPrice = document.createElement("p");
+
-    newPrice.innerText = price?.convertedPrice?.formatted ?? "NO PRICE";
+	const link = h(
-    newPrice.style.fontWeight = "bold";
+		"a",
-    link.appendChild(oldPrice);
+		{
-    link.appendChild(newPrice);
+			style: { textDecoration: "underline" },
-    container.appendChild(link);
+			href: bookUrl(countryCode),
-  });
+			target: "_blank",
+		},
+		countryCode.toUpperCase(),
+	);
+
+	const checkbox = h("input", {
+		type: "checkbox",
+		checked: isSelected,
+		onChange: () => toggleCountry(),
+	});
+
+	const priceLabel = h(
+		"p",
+		{ style: { fontWeight: "bold" } },
+		formatPrice(countryPrice, convertedPrice, isSelected),
+	);
+
+	return h(
+		"label",
+		{ style, onMouseEnter: hover, onMouseLeave: leave },
+		h("div", { style: { display: "flex" } }, checkbox, link),
+		priceLabel,
+	);
 };
 
-async function main() {
+const InLibrary = () =>
-  const container = createPricesContainer();
+	h(
+		"div",
+		{
+			style: {
+				display: "flex",
+				flexDirection: "column",
+				border: "1px solid black",
+				textAlign: "center",
+			},
+		},
+		h("h2", null, "Already in Library!"),
+	);
 
-  container.innerText = "LOADING PRICES...";
+const Percent = (percent) => {
+	const spinner = useRef();
 
-  try {
+	useEffect(() => {
-    initCache();
+		spinner.current.animate(
+			[{ transform: "rotate(0deg)" }, { transform: "rotate(360deg)" }],
+			{ iterations: Infinity, duration: 1000 },
+		);
+	}, []);
 
-    const countriesPrice = await getPrices();
+	const style = { padding: "10px 10px 0 10px", textAlign: "center" };
 
-    l("country prices", countriesPrice);
+	if (percent == 100) return h("h2", { style }, "all prices are loaded!");
 
-    sortPrices(countriesPrice);
+	return h(
+		"h2",
+		{ style },
+		`${percent}%`,
+		h("span", {
+			ref: spinner,
+			style: {
+				width: "16px",
+				height: "16px",
+				borderRadius: "50%",
+				display: "inline-block",
+				borderTop: "3px solid black",
+				borderRight: "3px solid transparent",
+				boxSizing: "border-box",
+				marginLeft: "15px",
+			},
+		}),
+	);
+};
 
-    l("sorted prices", countriesPrice);
+const Header = (state, percentChecked) => {
+	if (state === "loading") return Percent(percentChecked);
 
-    showPrices(container, countriesPrice);
+	if (state === "done")
-  } catch (e) {
+		return h(
-    l("error", e);
+			"h2",
-    container.innerText = "FAILED TO LOAD PRICES. CHECK CONSOLE FOR MORE INFO";
+			{ style: { textAlign: "center" } },
-  } finally {
+			"All prices are loaded!",
-    l("done");
+		);
-  }
+
-}
+	return h(
+		"h2",
+		{ style: { textAlign: "center" } },
+		'Select countries or leave as is and press "load"',
+	);
+};
+
+const Load = (state, load) => {
+	return h(
+		"button",
+		{
+			disabled: state === "loading",
+			onClick: load,
+			type: "button",
+			style: { backgroundColor: "#91ff91" },
+		},
+		state === "loading" ? "Loading..." : "Load prices",
+	);
+};
+
+const App = () => {
+	const { isSelected, toggleCountry, selected } = useSelectedCountries();
+	const { prices, percentChecked, state, load } = usePrices(selected);
+
+	l(selected);
+	const style = {
+		display: "flex",
+		flexDirection: "column",
+		border: "1px solid black",
+	};
+
+	if (isInLibrary()) {
+		return InLibrary();
+	}
+
+	return h(
+		"div",
+		{ style },
+		Header(state, percentChecked),
+		...prices.map((price) =>
+			h(Price, {
+				price,
+				toggleCountry: () => toggleCountry(price.countryCode),
+				isSelected: isSelected(price.countryCode),
+				isLoading: state,
+			}),
+		),
+		Load(state, load),
+	);
+};
 
 l("starting...");
-
+initCache();
-window.onload = () => {
+render(createElement(App), createPricesContainer());
-  l("page is fully loaded");
-  void main();
-};

lib/useCountries.js

@@ -0,0 +1,22 @@
+import "./logger";
+
+import { useCallback, useEffect, useState } from "preact/hooks";
+import { cacheSelectedCountries, getSelectedCountries } from "./cache";
+
+export const useSelectedCountries = () => {
+	const [selected, setSelected] = useState(() => getSelectedCountries());
+
+	useEffect(() => cacheSelectedCountries(selected), [selected]);
+
+	const toggleCountry = useCallback((countryCode) =>
+		setSelected({ ...selected, [countryCode]: !selected[countryCode] }),
+	);
+
+	const isSelected = useCallback((countryCode) => !!selected[countryCode]);
+
+	return {
+		selected,
+		toggleCountry,
+		isSelected,
+	};
+};

lib/usePrices.js

@@ -0,0 +1,61 @@
+import { useCallback, useState } from "preact/hooks";
+import { bookPriceFor } from "./bookPriceFor";
+import { COUNTRIES } from "./countries";
+
+const sortPrices = (prices, selectedCountries) =>
+	prices.sort((a, b) => {
+		if (!selectedCountries[a.countryCode]) return 1;
+		if (!selectedCountries[b.countryCode]) return -1;
+
+		return (
+			(a?.convertedPrice?.intValue || Infinity) -
+			(b?.convertedPrice?.intValue || Infinity)
+		);
+	});
+
+export const usePrices = (selectedCountries) => {
+	const [prices, setPrices] = useState(COUNTRIES);
+	const [state, setState] = useState("init");
+
+	const load = useCallback(async () => {
+		setState("loading");
+		for (let index = 0; index < prices.length; index += 2) {
+			if (!selectedCountries[prices[index].countryCode]) continue;
+
+			// intentionally blocking execution
+			// to resolve sequentially.
+			// It should prevent DOS and triggering captcha
+			if (index + 1 < prices.length) {
+				const [first, second] = await Promise.all([
+					bookPriceFor(prices[index]),
+					bookPriceFor(prices[index + 1]),
+				]);
+				prices[index] = first;
+				prices[index + 1] = second;
+			} else {
+				prices[index] = await bookPriceFor(prices[index]);
+			}
+
+			setPrices([...prices]);
+		}
+		setState("done");
+		l("DONE");
+	}, [selectedCountries]);
+
+	const selectedCount = Object.entries(selectedCountries)
+		.map(([_, selected]) => selected)
+		.filter(Boolean).length;
+
+	const alreadyLoaded = prices.filter(
+		(p) => p.countryPrice != undefined && selectedCountries[p.countryCode],
+	).length;
+
+	const percentChecked = (alreadyLoaded / selectedCount) * 100;
+
+	return {
+		prices: sortPrices(prices, selectedCountries),
+		percentChecked: percentChecked.toFixed(2),
+		load,
+		state,
+	};
+};

manifest.json

@@ -1,9 +1,8 @@
 {
   "name": "Kobo Price",
   "description": "Find lowest book price on kobo.com",
-  "version": "1.1.1",
+  "version": "1.3.0",
   "manifest_version": 3,
-  "permissions": ["activeTab"],
   "content_scripts": [
     {
       "js": ["dist/index.js"],
@@ -18,5 +17,12 @@
     "gecko": {
       "id": "koboprice@tertyshny.dev"
     }
+  },
+  "icons": {
+    "16": "icons/16.png",
+    "32": "icons/32.png",
+    "48": "icons/48.png",
+    "128": "icons/128.png"
   }
+ 
 }

package-lock.json

@@ -10,7 +10,8 @@
       "license": "ISC",
       "dependencies": {
         "currency.js": "^2.0.4",
-        "date-fns": "^3.6.0"
+        "date-fns": "^3.6.0",
+        "preact": "^10.22.1"
       },
       "devDependencies": {
         "@eslint/js": "^9.6.0",
@@ -4868,6 +4869,15 @@
       "integrity": "sha512-cHjPPsE+vhj/tnhCy/wiMh3M3z3h/j15zHQX+S9GkTBgqJuTuJzYJ4gUyACLhDaJ7kk9ba9iRDmbH2tJU03OiA==",
       "dev": true
     },
+    "node_modules/preact": {
+      "version": "10.22.1",
+      "resolved": "https://registry.npmjs.org/preact/-/preact-10.22.1.tgz",
+      "integrity": "sha512-jRYbDDgMpIb5LHq3hkI0bbl+l/TQ9UnkdQ0ww+lp+4MMOdqaUYdFc5qeyP+IV8FAd/2Em7drVPeKdQxsiWCf/A==",
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/preact"
+      }
+    },
     "node_modules/prelude-ls": {
       "version": "1.2.1",
       "resolved": "https://registry.npmjs.org/prelude-ls/-/prelude-ls-1.2.1.tgz",

package.json

@@ -7,10 +7,13 @@
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1",
     "lint": "eslint --fix",
-    "build": "esbuild lib/index.js --bundle --minify --sourcemap --target=chrome58,firefox57,safari11 --outfile=dist/index.js",
+    "bundle": "esbuild lib/index.js --bundle --minify --sourcemap --target=chrome58,firefox57,safari11 --outfile=dist/index.js",
-    "watch-build": "npm run build -- --watch",
+    "watch-bundle": "npm run bundle -- --watch",
-    "watch-ext": "web-ext run --start-url kobo.com",
+    "watch-ext": "web-ext run --start-url https://www.kobo.com/ww/en/ebook/foundation-the-foundation-trilogy-book-1-1",
-    "watch": "concurrently npm:watch-build npm:watch-ext"
+    "watch": "concurrently npm:watch-bundle npm:watch-ext",
+    "build-userscript": "cat userscript/koboprice.meta.js dist/index.js > userscript/koboprice.user.js",
+    "build-ext": "web-ext build",
+    "build-all": "npm run bundle && npm run build-userscript && rm -rf web-ext-artifacts && npm run build-ext"
   },
   "author": "",
   "license": "ISC",
@@ -27,6 +30,7 @@
   },
   "dependencies": {
     "currency.js": "^2.0.4",
-    "date-fns": "^3.6.0"
+    "date-fns": "^3.6.0",
+    "preact": "^10.22.1"
   }
 }