Clean up and document unused i18n token finder script

tools/possibly-unused-i18n-token-finder.js

@@ -0,0 +1,118 @@
+/**
+ * Possibly Unused i18n Token Finder
+ * Key word: POSSIBLY
+ *
+ * Looks for i18n tokens that MAY be unused by the code
+ * Since some tokens are generated dynamically, the list generated by this script
+ * should ALWAYS be verified manually before removing any of the tokens in it
+ *
+ * Ghostery Browser Extension
+ * http://www.ghostery.com/
+ *
+ * Copyright 2019 Ghostery, Inc. All rights reserved.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0
+ */
+
+// eslint-disable-next-line import/no-extraneous-dependencies
+const fs = require('fs');
+// eslint-disable-next-line import/no-extraneous-dependencies
+const jsonfile = require('jsonfile');
+
+// Constants
+const DEFAULT_LOCALE_TOKENS_FILE = './_locales/en/messages.json';
+const UNUSED_TOKENS_FILE = './tools/i18n_results/unused_tokens.txt';
+
+function saveListOfUnusedTokensToFile(filepath, unusedTokens) {
+	fs.writeFileSync(
+		filepath,
+		unusedTokens.join('\n')
+	);
+}
+
+function findUnusedTokens(tokens, filepaths) {
+	tokens = tokens.map(token => ({ value: token, isUsed: false }));
+
+	filepaths.forEach((filepath) => {
+		const fileContents = fs.readFileSync(filepath, 'utf8');
+		tokens.forEach((token) => {
+			if (token.isUsed) { return; }
+
+			// THE TEST
+			if (fileContents.includes(`t('${token.value}`)) {
+				token.isUsed = true;
+			}
+		});
+	});
+
+	const unusedTokens =
+		(tokens.filter(token => token.isUsed === false))
+			.map(token => token.value);
+
+	return unusedTokens;
+}
+
+/**
+ * Recursively collect the filepaths of files that
+ * satisfy the supplied extension and file system location conditions
+ * @param [Array|object] whereToLookAndForWhatExtensions
+ * @param [string Array] filepaths							The matching filepaths
+ * @returns [string Array] filepaths						The matching filepaths
+ */
+function getFilepaths(whereToLookAndForWhatExtensions, filepaths = []) {
+	const target = whereToLookAndForWhatExtensions;
+
+	if (Array.isArray(target)) {
+		target.forEach((t) => {
+			filepaths = getFilepaths(t, filepaths);
+		});
+	} else {
+		const dirEntries = fs.readdirSync(target.dir, { withFileTypes: true });
+
+		dirEntries.forEach((dirEntry) => {
+			if (dirEntry.isDirectory()) {
+				filepaths = getFilepaths({
+					dir: `${target.dir}/${dirEntry.name}`,
+					extensions: target.extensions
+				}, filepaths);
+			} else if (dirEntry.isFile()) {
+				if (target.extensions.some(extension => dirEntry.name.endsWith(extension))) {
+					filepaths.push(`${target.dir}/${dirEntry.name}`);
+				}
+			}
+		});
+
+		return filepaths;
+	}
+
+	return filepaths;
+}
+
+function getJSONKeys(filepath) {
+	const json = jsonfile.readFileSync(filepath);
+	return Object.keys(json);
+}
+
+saveListOfUnusedTokensToFile(
+	UNUSED_TOKENS_FILE,
+	findUnusedTokens(
+		getJSONKeys(DEFAULT_LOCALE_TOKENS_FILE),
+		getFilepaths(
+			[
+				// Overly broad, but we favor simplicity since there is no compelling reason here to favor performance / efficiency
+				// Also, we prefer that unused tokens be incorrectly reported as used than vice versa
+				{ dir: './app', extensions: ['.jsx', '.js'] },
+				{ dir: './src', extensions: ['.js'] },
+			]
+		)
+	)
+);
+
+console.log('\nPLEASE NOTE:');
+console.log('Since some i18n tokens are generated dynamically,')
+console.log('and since some others are formatted in a non-standard way,');
+console.log('the list generated by this script should ALWAYS');
+console.log('be verified manually before removing any of the tokens in it.');
+console.log('\nThe results are in ./tools/i18n_results/unused_tokens.txt');