Implement core of a tool that identifies unused i18n tokens

tools/unused-i18n-token-finder.js

@@ -0,0 +1,130 @@
+/**
+ * i18n Unused Tokens Checker
+ * * Combs through default local messages.json file looking for tokens that are not used in the project
+ * * Writes the results to a file
+ * * Results should be manually verified before removing any tokens because some tokens are dynamically generated
+ * 	 and this simple script does not account for that
+ *
+ * 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 import/no-extraneous-dependencies: 0 */
+/* eslint no-console: 0 */
+
+const fs = require('fs-extra');
+const jsonfile = require('jsonfile')
+
+// Constants
+const UNUSED_TOKENS_FILE = './tools/i18n_results/unused_tokens.txt';
+
+// Empty tools/i18n_results directory
+fs.emptyDirSync('./tools/i18n_results');
+
+
+/**
+ * Outputs the contents of an object to a .txt file.
+ * @param  string fileName       The location of the file we will output to
+ * @param  object resultsObject  An object with the data we will output
+ * @return none
+ */
+
+function recordResults(fileName, resultsObject) {
+	const stream = fs.createWriteStream(fileName);
+	stream.once('open', () => {
+		Object.keys(resultsObject).forEach((key) => {
+			stream.write(`${key}[${resultsObject[key].length}]:\n`);
+			resultsObject[key].forEach((duplicate) => {
+				stream.write(`${duplicate}\n`);
+			});
+			stream.write('\n');
+		});
+		stream.end();
+	});
+}
+
+function findUnusedTokens(tokens, filepaths) {
+	tokens = tokens.map(token => ({ value: token, isUsed: false }));
+
+	// Simpler than splicing arrays
+	filepaths.forEach((filepath) => {
+		const fileContents = fs.readFileSync(filepath, 'utf8');
+		tokens.forEach((token) => {
+			if (token.isUsed) { return; }
+
+			if (fileContents.includes(token.value)) {
+				token.isUsed = true;
+			}
+		});
+	});
+
+	const unusedTokens =
+		(tokens.filter(token => token.isUsed === false))
+			.map(token => token.value);
+
+	return unusedTokens;
+}
+
+/**
+ * Recursively collect the filepaths of files that
+ * satisfy the supplied extension and file system location conditions
+ * @param [Array|object] whereToLookAndForWhatExtensions
+ * @param [string Array] filepaths							The matching filepaths
+ * @returns [string Array] filepaths						The matching filepaths
+ */
+function getFilepaths(whereToLookAndForWhatExtensions, filepaths = []) {
+	const targets = whereToLookAndForWhatExtensions;
+
+	if (Array.isArray(targets)) {
+		targets.forEach((target) => {
+			filepaths = getFilepaths(target, filepaths);
+		});
+	} else {
+		const dirEntries = fs.readdirSync(targets.dir, { withFileTypes: true });
+
+		dirEntries.forEach((dirEntry) => {
+			if (dirEntry.isDirectory()) {
+				filepaths = getFilepaths({
+					dir: `${targets.dir}/${dirEntry.name}`,
+					extensions: targets.extensions
+				}, filepaths);
+			}
+			if (dirEntry.isFile()) {
+				if (targets.extensions.some(extension => dirEntry.name.endsWith(extension))) {
+					filepaths.push(`${targets.dir}/${dirEntry.name}`);
+				};
+			};
+		});
+
+		return filepaths;
+	}
+
+	return filepaths;
+}
+
+function getJSONKeys(filepath) {
+	const json = jsonfile.readFileSync(filepath);
+	return Object.keys(json);
+}
+
+console.time('i18n-unused-tokens-checker.js');
+// recordResults(
+	findUnusedTokens(
+		getJSONKeys('./_locales/en/messages.json'),
+		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 (due to an overbroad search) than vice versa
+				{ dir: './app', extensions: ['.jsx', '.js'] },
+				{ dir: './src', extensions: ['.js'] },
+			]
+		)
+	);
+//);
+console.timeEnd('i18n-unused-tokens-checker.js');