Enable prefer-const lint rule (#3202)

src/cli/parse-server.js

@@ -35,7 +35,7 @@ function startServer(options, callback) {
 
   app.use(options.mountPath, api);
 
-  let server = app.listen(options.port, options.host, callback);
+  const server = app.listen(options.port, options.host, callback);
   server.on('connection', initializeConnections);
 
   if (options.startLiveQueryServer || options.liveQueryServerOptions) {
@@ -69,7 +69,7 @@ function startServer(options, callback) {
     }
   }
 
-  let handleShutdown = function() {
+  const handleShutdown = function() {
     console.log('Termination signal received. Shutting down.');
     destroyAliveConnections();
     server.close(function () {

src/cli/utils/commander.js

@@ -68,7 +68,7 @@ function parseConfigFile(program) {
   if (program.args.length > 0) {
     let jsonPath = program.args[0];
     jsonPath = path.resolve(jsonPath);
-    let jsonConfig = require(jsonPath);
+    const jsonConfig = require(jsonPath);
     if (jsonConfig.apps) {
       if (jsonConfig.apps.length > 1) {
         throw 'Multiple apps are not supported';
@@ -78,11 +78,11 @@ function parseConfigFile(program) {
       options = jsonConfig;
     }
     Object.keys(options).forEach((key) => {
-      let value = options[key];
+      const value = options[key];
       if (!_definitions[key]) {
         throw `error: unknown option ${key}`;
       }
-      let action = _definitions[key].action;
+      const action = _definitions[key].action;
       if (action) {
         options[key] = action(value);
       }

src/cli/utils/runner.js

@@ -2,7 +2,7 @@
 import program from './commander';
 
 function logStartupOptions(options) {
-  for (let key in options) {
+  for (const key in options) {
     let value = options[key];
     if (key == "masterKey") {
       value = "***REDACTED***";
@@ -31,7 +31,7 @@ export default function({
   }
   program.parse(process.argv, process.env);
 
-  let options = program.getOptions();
+  const options = program.getOptions();
   start(program, options, function() {
     logStartupOptions(options);
   });