Add script to check that NPM website has correct versions

src/check-npm-website.ts

@@ -0,0 +1,75 @@
+/*
+Usage:
+
+	npm run build
+	npm run clean
+	npm run get-definitely-typed
+	npm run parse
+	npm run calculate-versions
+	node ./bin/check-npm-website.js
+*/
+
+import fetch = require("node-fetch");
+import { TypingsData, fullPackageName, readTypesDataFile, typingsFromData } from "./lib/common";
+import { done, nAtATime } from "./lib/util";
+import Versions, { changedPackages } from "./lib/versions";
+
+if (!module.parent) {
+	done(main());
+}
+
+/**
+ * Downloads package packages from npmjs.com and checks that it reflects the latest published version.
+ */
+async function main(): Promise<void> {
+	const [typeData, versions] = await Promise.all([readTypesDataFile(), Versions.load()]);
+	const typings = typingsFromData(typeData);
+	const changed = await changedPackages(typings);
+	const outdated: TypingsData[] = [];
+
+	await nAtATime(25, typings, async typing => {
+		if (!changed.includes(typing)) {
+			if (!await checkSingle(typing, versions.versionInfo(typing).version)) {
+				outdated.push(typing);
+			}
+		}
+	});
+
+	console.log(`The following are outdated: ${outdated.map(t => t.typingsPackageName)}`);
+}
+
+/** Returns true if npm is up-to-date. */
+async function checkSingle(typing: TypingsData, correctVersion: number): Promise<boolean> {
+	const name = typing.typingsPackageName;
+	const url = `https://www.npmjs.com/package/${fullPackageName(name)}`;
+	console.log(`Checking ${name}...`);
+	const content = await fetchTextWithRetries(url);
+
+	const rgx = /<strong>\d+\.\d+\.(\d+)<\/strong>\s+is the latest/;
+	const match = rgx.exec(content);
+	if (match === null) {
+		throw new Error(`${name} has unexpected content:\n${content}`);
+	}
+
+	const websiteVersion = match[1];
+	const upToDate = websiteVersion === correctVersion.toString();
+	if (!upToDate) {
+		console.log(`OUTDATED: ${name}: Expected ${correctVersion}, got ${websiteVersion}`);
+	}
+	return upToDate;
+}
+
+async function fetchTextWithRetries(url: string, retries: number = 5): Promise<string> {
+	while (retries > 0) {
+		const response = await fetch(url);
+		// Gateway Time-out
+		if (response.status !== 200) {
+			console.log(`Retrying ${url}...`);
+			retries--;
+		}
+		else {
+			return response.text();
+		}
+	}
+	throw new Error(`Can't fetch ${url} even after retrying`);
+}