Apply prefer-const lint rule

lib/extensions.js

@@ -29,7 +29,7 @@ const processes = {};
 const jobs = {};
 
 function messageHandler(message) {
-  let func = jobs[message[0]];
+  const func = jobs[message[0]];
   if (func) {
     delete jobs[message[0]];
     func(null, message[1], message[2]);
@@ -37,10 +37,10 @@ function messageHandler(message) {
 }
 
 function run(args, callback) {
-  let scriptName = args[0];
+  const scriptName = args[0];
 
   if (!processes[scriptName]) {
-    let p = childProcess.fork("lib/extension-wrapper", [scriptName]);
+    const p = childProcess.fork("lib/extension-wrapper", [scriptName]);
     processes[scriptName] = p;
 
     p.on("error", () => {
@@ -60,7 +60,7 @@ function run(args, callback) {
     p.on("message", messageHandler);
   }
 
-  let id = crypto.randomBytes(8).toString("hex");
+  const id = crypto.randomBytes(8).toString("hex");
   jobs[id] = callback;
   setTimeout(() => {
     if (id in jobs) {
@@ -75,11 +75,11 @@ function run(args, callback) {
 function kill(process, callback) {
   if (process.signalCode !== null || process.exitCode !== null) return;
 
-  let timeToKill = Date.now() + 5000;
+  const timeToKill = Date.now() + 5000;
 
   process.kill();
 
-  let t = setInterval(() => {
+  const t = setInterval(() => {
     if (process.signalCode !== null || process.exitCode !== null) {
       clearInterval(t);
       if (callback) callback();
@@ -93,7 +93,7 @@ function kill(process, callback) {
 
 function killAll(callback) {
   let counter = 1;
-  for (let n in processes) {
+  for (const n in processes) {
     ++counter;
     kill(processes[n], () => {
       if (--counter == 0 && callback) callback();