replace let with const

Author: vitpavlenko

JavaScript/4-promises.js

@@ -6,7 +6,7 @@ const promisify = require('./promisify');
 const readFile = promisify(fs.readFile);
 
 function readTextFile(filename) {
-  let promise = readFile(filename).then(data => data.toString());
+  const promise = readFile(filename).then(data => data.toString());
   return promise;
 }
 

JavaScript/5-catch.js

@@ -6,7 +6,7 @@ const promisify = require('./promisify');
 const readFile = promisify(fs.readFile);
 
 function readTextFile(filename) {
-  let promise = readFile(filename).then(data => data.toString());
+  const promise = readFile(filename).then(data => data.toString());
   return promise;
 }
 

JavaScript/6-onReject.js

@@ -6,7 +6,7 @@ const promisify = require('./promisify');
 const readFile = promisify(fs.readFile);
 
 function readTextFile(filename) {
-  let promise = readFile(filename).then(data => data.toString());
+  const promise = readFile(filename).then(data => data.toString());
   return promise;
 }
 

JavaScript/8-http.js

@@ -4,8 +4,8 @@ const httpGet = require('./get-json');
 
 const baseUrl = 'http://localhost:3000/';
 httpGet(baseUrl).then((api) => {
-  let promises = [];
-  for (let resource of api.resources) {
+  const promises = [];
+  for (const resource of api.resources) {
     promises.push(httpGet(baseUrl + resource));
   }
   Promise.all(promises).then((values) => {

JavaScript/9-http.js

@@ -5,9 +5,9 @@ const async = require('./async');
 
 const baseUrl = 'http://localhost:3000/';
 async(function* () {
-  let api = yield httpGet(baseUrl);
-  for (let resource of api.resources) {
-    let data = yield httpGet(baseUrl + resource);
+  const api = yield httpGet(baseUrl);
+  for (const resource of api.resources) {
+    const data = yield httpGet(baseUrl + resource);
     console.log(data);
   }
 });

JavaScript/async-await/http-client.js

@@ -5,9 +5,9 @@ import httpGet from '../get-json';
 const baseUrl = 'http://localhost:3000/';
 
 (async () => {
-  let api = await httpGet(baseUrl);
-  for (let resource of api.resources) {
-    let data = await httpGet(baseUrl + resource);
+  const api = await httpGet(baseUrl);
+  for (const resource of api.resources) {
+    const data = await httpGet(baseUrl + resource);
     console.log(data);
   }
-})();
+})();

JavaScript/async.js

@@ -1,14 +1,14 @@
 'use strict';
 
 module.exports = (asyncFn) => {
-  let generator = asyncFn();
+  const generator = asyncFn();
   let result = generator.next();
 
   return new Promise((resolve, reject) => {
     step();
 
     function step() {
-      let promise = Promise.resolve(result.value);
+      const promise = Promise.resolve(result.value);
 
       if (result.done) {
         resolve(promise);

JavaScript/get-json.js

@@ -5,20 +5,20 @@ const http = require('http');
 module.exports = (url) => {
   return new Promise((resolve, reject) => {
     http.get(url, res => {
-      let code = res.statusCode;
+      const code = res.statusCode;
       if (code !== 200) {
         return reject(new Error(`HTTP status code ${code}`));
       }
 
       res.on('error', reject);
 
-      let chunks = [];
+      const chunks = [];
       res.on('data', chunk => {
         chunks.push(chunk);
       });
 
       res.on('end', () => {
-        let json = Buffer.concat(chunks).toString();
+        const json = Buffer.concat(chunks).toString();
         let object = null;
 
         try {

JavaScript/promisify.js

@@ -10,7 +10,7 @@ module.exports = function promisify(asyncFunction) {
           resolve(result);
         }
       });
-      asyncFunction.apply(undefined, args);
+      asyncFunction(...args);
     });
   };
 };

JavaScript/server.js

@@ -27,21 +27,21 @@ const routes = {
 };
 
 const server = http.createServer((req, res) => {
-  let parsedUrl = url.parse(req.url);
+  const parsedUrl = url.parse(req.url);
   let path = parsedUrl.pathname;
   if (path.endsWith('/') && path.length > 1) {
     path = path.slice(0, -1);
   }
 
-  let handler = routes[path];
+  const handler = routes[path];
   if (!handler) {
     res.writeHead(404);
     res.end('Not found');
     return;
   }
 
   handler(req, (result) => {
-    let json = JSON.stringify(result);
+    const json = JSON.stringify(result);
     res.writeHead(200, { 'Content-Type': 'application/json' });
     res.end(json);
   });