Added new module for importing JSON files safely, along with test files

lib/__tests__/importJSON.test.js

@@ -0,0 +1,42 @@
+'use strict';
+
+const importJSON = require('../importJSON');
+const matchers = require('jest-extended');
+const fs = require('fs');
+
+expect.extend(matchers);
+
+describe('importJSON', () => {
+	test('Import a file from config dir if no dir param given', () => {
+		const loadedFile = importJSON('db.sample');
+
+		expect(loadedFile).toBeObject();
+		expect(loadedFile.host).toBe('hostname');
+		expect(loadedFile.port).toBeNumber();
+		expect(loadedFile.port).toBe(1111);
+	});
+
+	test('Import a file from specified dir', () => {
+		const loadedFile = importJSON('db.sample', 'config');
+
+		expect(loadedFile).toBeObject();
+		expect(loadedFile.host).toBe('hostname');
+		expect(loadedFile.port).toBeNumber();
+		expect(loadedFile.port).toBe(1111);
+	});
+
+	test('Fail if file doesn\'t exist', () => {
+		expect(() => importJSON('bob'))
+			.toThrowError('Missing file');
+	});
+
+	test('Fail if file is malformed', () => {
+		fs.mkdirSync('config/test');
+		fs.writeFileSync('config/test/test.json', 'bob');
+
+		expect(() => importJSON('test', 'config/test'))
+			.toThrowError('Malformed file');
+
+		fs.rmSync('config/test', { recursive: true });
+	});
+});

lib/importJSON.js

@@ -0,0 +1,33 @@
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+
+/**
+ * importJSON() Function to safely fetch and parse a JSON file
+ *
+ * @param {string} filename - The filename of the json file to be loaded
+ * @param {string} [dir='config'] - The directory to find the JSON file in
+ *
+ * @return {Object} The loaded object from the file
+ */
+function importJSON(filename, dir='config') {
+	const fullFilename = `${filename}.json`;
+	const pathToFile = path.join(__dirname, '..', dir, fullFilename);
+
+	// Validate that a file exists with that name within the config dir
+	if (!fs.existsSync(pathToFile))
+		throw new Error(`Missing file (${pathToFile})`);
+
+	// Import the file
+	let file;
+	try {
+		file = require(pathToFile);
+	} catch {
+		throw new Error(`Malformed file (${pathToFile})`);
+	}
+
+	return file;
+}
+
+module.exports = importJSON;