Use let/const instead of var, #104

.eslintrc

@@ -97,6 +97,7 @@
     vars-on-top: 0,
     wrap-iife: [2, "inside"],
     yoda: 2,
+    no-var: "error",
 
     // Strict Mode
     strict: [2, "never"],

packages/core/lib/CliRunner.js

@@ -1,12 +1,12 @@
 /*! @license MIT ©2013-2017 Ruben Verborgh and Ruben Taelman, Ghent University - imec */
 /* Logic for starting an LDF server with a given config from the command line. */
 
-var cluster = require('cluster'),
+let cluster = require('cluster'),
     ComponentsLoader = require('componentsjs').Loader;
 
 // Run function for starting the server from the command line
 function runCli(moduleRootPath) {
-  var argv = process.argv.slice(2);
+  let argv = process.argv.slice(2);
   runCustom(argv, process.stdin, process.stdout, process.stderr, null, { mainModulePath: moduleRootPath });
 }
 
@@ -17,11 +17,11 @@ function runCustom(args, stdin, stdout, stderr, componentConfigUri, properties)
     return process.exit(1);
   }
 
-  var cliPort = parseInt(args[1], 10),
+  let cliPort = parseInt(args[1], 10),
       cliWorkers = parseInt(args[2], 10),
       configUri = args[3] || componentConfigUri || 'urn:ldf-server:my';
 
-  var loader = new ComponentsLoader(properties);
+  let loader = new ComponentsLoader(properties);
   loader.registerAvailableModuleResources()
     .then(function () {
       // Start up a cluster master
@@ -57,11 +57,11 @@ function runCustom(args, stdin, stdout, stderr, componentConfigUri, properties)
     });
 
   function startClusterMaster(config) {
-    var workers = cliWorkers || config.workers || 1;
+    let workers = cliWorkers || config.workers || 1;
 
     // Create workers
     stdout.write('Master ' + process.pid + ' running.\n');
-    for (var i = 0; i < workers; i++)
+    for (let i = 0; i < workers; i++)
       cluster.fork();
 
     // Respawn crashed workers
@@ -86,14 +86,14 @@ function runCustom(args, stdin, stdout, stderr, componentConfigUri, properties)
       process.removeListener('SIGHUP', respawn);
 
       // Retrieve a list of old workers that will be replaced by new ones
-      var workers = Object.keys(cluster.workers).map(function (id) { return cluster.workers[id]; });
+      let workers = Object.keys(cluster.workers).map(function (id) { return cluster.workers[id]; });
       (function respawnNext() {
         // If there are still old workers, respawn a new one
         if (workers.length) {
           // Wait until the new worker starts listening to kill the old one
-          var newWorker = cluster.fork();
+          let newWorker = cluster.fork();
           newWorker.once('listening', function () {
-            var worker = workers.pop();
+            let worker = workers.pop();
             if (!worker)
               return newWorker.kill(), respawnNext(); // Dead workers are replaced automatically
             worker.once('exit', function () {

packages/core/lib/LinkedDataFragmentsServer.js

@@ -1,7 +1,7 @@
 /*! @license MIT ©2014-2016 Ruben Verborgh, Ghent University - imec */
 /* LinkedDataFragmentsServer is an HTTP server that provides access to Linked Data Fragments */
 
-var _ = require('lodash'),
+let _ = require('lodash'),
     fs = require('fs'),
     Util = require('./Util'),
     ErrorController = require('./controllers/ErrorController'),
@@ -11,14 +11,14 @@ var _ = require('lodash'),
 class LinkedDataFragmentsServer {
   constructor(options) {
     // Create the HTTP(S) server
-    var server, sockets = 0;
-    var urlData = options && options.urlData ? options.urlData : new UrlData();
+    let server, sockets = 0;
+    let urlData = options && options.urlData ? options.urlData : new UrlData();
     switch (urlData.protocol) {
     case 'http':
       server = require('http').createServer();
       break;
     case 'https':
-      var ssl = options.ssl || {}, authentication = options.authentication || {};
+      const ssl = options.ssl || {}, authentication = options.authentication || {};
       // WebID authentication requires a client certificate
       if (authentication.webid)
         ssl.requestCert = ssl.rejectUnauthorized = true;
@@ -29,7 +29,7 @@ class LinkedDataFragmentsServer {
     }
 
     // Copy over members
-    for (var member in LinkedDataFragmentsServer.prototype)
+    for (let member in LinkedDataFragmentsServer.prototype)
       server[member] = LinkedDataFragmentsServer.prototype[member];
 
     // Assign settings
@@ -48,7 +48,7 @@ class LinkedDataFragmentsServer {
       catch (error) { server._reportError(request, response, error); }
     });
     server.on('connection', function (socket) {
-      var socketId = sockets++;
+      let socketId = sockets++;
       server._sockets[socketId] = socket;
       socket.on('close', function () { delete server._sockets[socketId]; });
     });
@@ -59,7 +59,7 @@ class LinkedDataFragmentsServer {
 // Handles an incoming HTTP request
 LinkedDataFragmentsServer.prototype._processRequest = function (request, response) {
   // Add default response headers
-  for (var header in this._defaultHeaders)
+  for (let header in this._defaultHeaders)
     response.setHeader(header, this._defaultHeaders[header]);
 
   // Verify an allowed HTTP method was used
@@ -81,7 +81,7 @@ LinkedDataFragmentsServer.prototype._processRequest = function (request, respons
   }
 
   // Try each of the controllers in order
-  var self = this, controllerId = 0;
+  let self = this, controllerId = 0;
   function nextController(error) {
     // Error if the previous controller failed
     if (error)
@@ -91,7 +91,7 @@ LinkedDataFragmentsServer.prototype._processRequest = function (request, respons
       response.emit('error', new Error('No controller for ' + request.url));
     // Otherwise, try the next controller
     else {
-      var controller = self._controllers[controllerId++], next = _.once(nextController);
+      let controller = self._controllers[controllerId++], next = _.once(nextController);
       try { controller.handleRequest(request, response, next); }
       catch (error) { next(error); }
     }
@@ -127,7 +127,7 @@ LinkedDataFragmentsServer.prototype._reportError = function (request, response,
 LinkedDataFragmentsServer.prototype.stop = function () {
   // Don't accept new connections, and close existing ones
   this.close();
-  for (var id in this._sockets)
+  for (let id in this._sockets)
     this._sockets[id].destroy();
 
   // Close all controllers

packages/core/lib/LinkedDataFragmentsServerWorker.js

@@ -1,7 +1,7 @@
 /*! @license MIT ©2014-2017 Ruben Verborgh and Ruben Taelman, Ghent University - imec */
 /* LinkedDataFragmentsServerRunner is able to run a Linked Data Fragments server */
 
-var _ = require('lodash'),
+let _ = require('lodash'),
     fs = require('fs'),
     LinkedDataFragmentsServer = require('./LinkedDataFragmentsServer');
 
@@ -17,7 +17,7 @@ class LinkedDataFragmentsServerWorker {
 
     // Create all data sources
     Object.keys(config.datasources).forEach(function (datasourceId) {
-      var datasource = config.datasources[datasourceId];
+      let datasource = config.datasources[datasourceId];
       datasource.on('error', datasourceError);
       function datasourceError(error) {
         config.datasources[datasourceId].hide = true;
@@ -26,11 +26,11 @@ class LinkedDataFragmentsServerWorker {
     });
 
     // Set up logging
-    var loggingSettings = config.logging;
+    let loggingSettings = config.logging;
     // eslint-disable-next-line no-console
     config.log = console.log;
     if (loggingSettings.enabled) {
-      var accesslog = require('access-log');
+      let accesslog = require('access-log');
       config.accesslogger = function (request, response) {
         accesslog(request, response, null, function (logEntry) {
           fs.appendFile(loggingSettings.file, logEntry + '\n', function (error) {
@@ -41,10 +41,10 @@ class LinkedDataFragmentsServerWorker {
     }
 
     // Make sure the 'last' controllers are last in the array and the 'first' are first.
-    var lastControllers = _.remove(config.controllers, function (controller) {
+    let lastControllers = _.remove(config.controllers, function (controller) {
       return controller._last;
     });
-    var firstControllers = _.remove(config.controllers, function (controller) {
+    let firstControllers = _.remove(config.controllers, function (controller) {
       return controller._first;
     });
     config.controllers = firstControllers.concat(config.controllers.concat(lastControllers));
@@ -54,16 +54,16 @@ class LinkedDataFragmentsServerWorker {
 
   // Start the worker
   run(port) {
-    var config = this._config;
+    let config = this._config;
     if (port)
       config.port = port;
-    var server = new LinkedDataFragmentsServer(config);
+    let server = new LinkedDataFragmentsServer(config);
 
     // Start the server when all data sources are ready
-    var pending = _.size(config.datasources);
+    let pending = _.size(config.datasources);
     _.each(config.datasources, function (datasource) {
       // Add datasource ready-listener
-      var ready = _.once(startWhenReady);
+      let ready = _.once(startWhenReady);
       datasource.once('initialized', ready);
       datasource.once('error', ready);
 

packages/core/lib/UrlData.js

@@ -14,7 +14,7 @@ class UrlData {
     this.assetsPath = this.baseURLPath + 'assets/' || options.assetsPath;
     this.protocol = options.protocol;
     if (!this.protocol) {
-      var protocolMatch = (this.baseURL || '').match(/^(\w+):/);
+      let protocolMatch = (this.baseURL || '').match(/^(\w+):/);
       this.protocol = protocolMatch ? protocolMatch[1] : 'http';
     }
   }

packages/core/lib/Util.js

@@ -13,7 +13,7 @@ module.exports.createErrorType = function (BaseError, name, init) {
   if (typeof BaseError !== 'function')
     init = name, name = BaseError, BaseError = Error;
   function ErrorType(message) {
-    var error = this instanceof ErrorType ? this : new ErrorType(message);
+    let error = this instanceof ErrorType ? this : new ErrorType(message);
     error.name = name;
     error.message = message || '';
     Error.captureStackTrace(error, error.constructor);

packages/core/lib/controllers/AssetsController.js

@@ -1,7 +1,7 @@
 /*! @license MIT ©2015-2016 Ruben Verborgh, Ghent University - imec */
 /* An AssetsController responds to requests for assets */
 
-var Controller = require('./Controller'),
+let Controller = require('./Controller'),
     fs = require('fs'),
     path = require('path'),
     mime = require('mime'),
@@ -15,13 +15,13 @@ class AssetsController extends Controller {
     super(options);
 
     // Set up path matching
-    var assetsPath = (options.urlData || new UrlData()).assetsPath || '/assets/';
+    let assetsPath = (options.urlData || new UrlData()).assetsPath || '/assets/';
     this._matcher = new RegExp('^' + Util.toRegExp(assetsPath) + '(.+)|^/(\\w*)\\.ico$');
 
     // Read all assets
-    var assetsFolders = options.assetsFolders || ['file:///' + path.join(__dirname, '../../assets/')];
+    let assetsFolders = options.assetsFolders || ['file:///' + path.join(__dirname, '../../assets/')];
     this._assets = {};
-    for (var i = 0; i < assetsFolders.length; i++)
+    for (let i = 0; i < assetsFolders.length; i++)
       this._readAssetsFolder(assetsFolders[i], '');
   }
 
@@ -30,10 +30,10 @@ class AssetsController extends Controller {
     if (assetsFolder.indexOf('file:///') === 0)
       assetsFolder = assetsFolder.replace('file:///', '');
     fs.readdirSync(assetsFolder).forEach(function (name) {
-      var filename = path.join(assetsFolder, name), stats = fs.statSync(filename);
+      let filename = path.join(assetsFolder, name), stats = fs.statSync(filename);
     // Read an asset file into memory
       if (stats.isFile()) {
-        var assetType = mime.lookup(filename);
+        let assetType = mime.lookup(filename);
         this._assets[assetsPath + name.replace(/[.][^.]+$/, '')] = {
           type: assetType.indexOf('text/') ? assetType : assetType + ';charset=utf-8',
           contents: fs.readFileSync(filename),
@@ -47,7 +47,7 @@ class AssetsController extends Controller {
 
   // Try to serve the requested asset
   _handleRequest(request, response, next) {
-    var assetMatch = request.url.match(this._matcher), asset;
+    let assetMatch = request.url.match(this._matcher), asset;
     if (asset = assetMatch && this._assets[assetMatch[1] || assetMatch[2]]) {
       response.writeHead(200, {
         'Content-Type': asset.type,

packages/core/lib/controllers/Controller.js

@@ -1,7 +1,7 @@
 /*! @license MIT ©2015-2016 Ruben Verborgh, Ghent University - imec */
 /* Controller is a base class for HTTP request handlers */
 
-var url = require('url'),
+let url = require('url'),
     _ = require('lodash'),
     ViewCollection = require('../views/ViewCollection'),
     UrlData = require('../UrlData'),
@@ -41,7 +41,7 @@ class Controller {
     }
 
     // Try to handle the request
-    var self = this;
+    let self = this;
     try { this._handleRequest(request, response, done, settings); }
     catch (error) { done(error); }
     function done(error) {
@@ -60,7 +60,7 @@ class Controller {
     if (!request.headers.forwarded)
       return {};
     try {
-      var forwarded = _.defaults.apply(this, parseForwarded(request.headers.forwarded));
+      let forwarded = _.defaults.apply(this, parseForwarded(request.headers.forwarded));
       return {
         protocol: forwarded.proto ? forwarded.proto + ':' : undefined,
         host: forwarded.host,
@@ -91,10 +91,10 @@ class Controller {
   // Finds an appropriate view using content negotiation
   _negotiateView(viewName, request, response) {
     // Indicate that the response is content-negotiated
-    var vary = response.getHeader('Vary');
+    let vary = response.getHeader('Vary');
     response.setHeader('Vary', 'Accept' + (vary ? ', ' + vary : ''));
     // Negotiate a view
-    var viewMatch = this._views.matchView(viewName, request);
+    let viewMatch = this._views.matchView(viewName, request);
     response.setHeader('Content-Type', viewMatch.responseType || viewMatch.type);
     return viewMatch.view;
   }

packages/core/lib/controllers/DereferenceController.js

@@ -1,7 +1,7 @@
 /*! @license MIT ©2015-2016 Ruben Verborgh, Ghent University - imec */
 /* A DeferenceController responds to dereferencing requests */
 
-var Controller = require('./Controller'),
+let Controller = require('./Controller'),
     url = require('url'),
     _ = require('lodash'),
     Util = require('../Util');
@@ -11,17 +11,17 @@ class DeferenceController extends Controller {
   constructor(options) {
     options = options || {};
     super(options);
-    var paths = this._paths = options.dereference || {};
+    let paths = this._paths = options.dereference || {};
     this._matcher = /$0^/;
     if (!_.isEmpty(paths))
       this._matcher = new RegExp('^(' + Object.keys(paths).map(Util.toRegExp).join('|') + ')');
   }
 
   // Dereferences a URL by redirecting to its subject fragment of a certain data source
   _handleRequest(request, response, next) {
-    var match = this._matcher.exec(request.url), datasource;
+    let match = this._matcher.exec(request.url), datasource;
     if (datasource = match && this._paths[match[1]]) {
-      var entity = url.format(_.defaults({
+      let entity = url.format(_.defaults({
         pathname: datasource.path,
         query: { subject: url.format(request.parsedUrl) },
       }, request.parsedUrl));

packages/core/lib/controllers/ErrorController.js

@@ -1,7 +1,7 @@
 /*! @license MIT ©2015-2016 Ruben Verborgh, Ghent University - imec */
 /* An ErrorController responds to requests that caused an error */
 
-var Controller = require('./Controller'),
+let Controller = require('./Controller'),
     Util = require('../Util');
 
 // Creates a new ErrorController
@@ -13,7 +13,7 @@ class ErrorController extends Controller {
   // Serves an error response
   _handleRequest(request, response, next) {
     // Try to write an error response through an appropriate view
-    var error = response.error || (response.error = new Error('Unknown error')),
+    let error = response.error || (response.error = new Error('Unknown error')),
         view = this._negotiateView('Error', request, response),
         metadata = { prefixes: this._prefixes, datasources: this._datasources, error: error };
     response.writeHead(500);

packages/core/lib/controllers/NotFoundController.js

@@ -1,7 +1,7 @@
 /*! @license MIT ©2015-2016 Ruben Verborgh, Ghent University - imec */
 /* A NotFoundController responds to requests that cannot be resolved */
 
-var Controller = require('./Controller'),
+let Controller = require('./Controller'),
     Util = require('../Util');
 
 // Creates a new NotFoundController
@@ -17,7 +17,7 @@ class NotFoundController extends Controller {
     response.setHeader('Cache-Control', 'public,max-age=3600');
 
     // Render the 404 message using the appropriate view
-    var view = this._negotiateView('NotFound', request, response),
+    let view = this._negotiateView('NotFound', request, response),
         metadata = { url: request.url, prefixes: this._prefixes, datasources: this._datasources };
     response.writeHead(404);
     view.render(metadata, request, response);