fix: use const instead of var in the README (request#3046)

README.md

@@ -16,7 +16,7 @@
 Request is designed to be the simplest way possible to make http calls. It supports HTTPS and follows redirects by default.
 
 ```js
-var request = require('request');
+const request = require('request');
 request('http://www.google.com', function (error, response, body) {
   console.log('error:', error); // Print the error if one occurred
   console.log('statusCode:', response && response.statusCode); // Print the response status code if a response was received
@@ -110,7 +110,7 @@ You can also `pipe()` from `http.ServerRequest` instances, as well as to `http.S
 ```js
 http.createServer(function (req, resp) {
   if (req.url === '/doodle.png') {
-    var x = request('http://mysite.com/doodle.png')
+    const x = request('http://mysite.com/doodle.png')
     req.pipe(x)
     x.pipe(resp)
   }
@@ -126,7 +126,7 @@ req.pipe(request('http://mysite.com/doodle.png')).pipe(resp)
 Also, none of this new functionality conflicts with requests previous features, it just expands them.
 
 ```js
-var r = request.defaults({'proxy':'http://localproxy.com'})
+const r = request.defaults({'proxy':'http://localproxy.com'})
 
 http.createServer(function (req, resp) {
   if (req.url === '/doodle.png') {
@@ -185,7 +185,7 @@ For `multipart/form-data` we use the [form-data](https://github.com/form-data/fo
 
 
 ```js
-var formData = {
+const formData = {
   // Pass a simple key-value pair
   my_field: 'my_value',
   // Pass data via Buffers
@@ -220,8 +220,8 @@ For advanced cases, you can access the form-data object itself via `r.form()`. T
 
 ```js
 // NOTE: Advanced use-case, for normal use see 'formData' usage above
-var r = request.post('http://service.com/upload', function optionalCallback(err, httpResponse, body) {...})
-var form = r.form();
+const r = request.post('http://service.com/upload', function optionalCallback(err, httpResponse, body) {...})
+const form = r.form();
 form.append('my_field', 'my_value');
 form.append('my_buffer', Buffer.from([1, 2, 3]));
 form.append('custom_file', fs.createReadStream(__dirname + '/unicycle.jpg'), {filename: 'unicycle.jpg'});
@@ -316,11 +316,11 @@ detailed in [RFC 1738](http://www.ietf.org/rfc/rfc1738.txt). Simply pass the
 `user:password` before the host with an `@` sign:
 
 ```js
-var username = 'username',
+const username = 'username',
     password = 'password',
     url = 'http://' + username + ':' + password + '@some.server.com';
 
-request({url: url}, function (error, response, body) {
+request({url}, function (error, response, body) {
    // Do more stuff with 'body' here
 });
 ```
@@ -349,9 +349,9 @@ of stars and forks for the request repository. This requires a
 custom `User-Agent` header as well as https.
 
 ```js
-var request = require('request');
+const request = require('request');
 
-var options = {
+const options = {
   url: 'https://api.github.com/repos/request/request',
   headers: {
     'User-Agent': 'request'
@@ -360,7 +360,7 @@ var options = {
 
 function callback(error, response, body) {
   if (!error && response.statusCode == 200) {
-    var info = JSON.parse(body);
+    const info = JSON.parse(body);
     console.log(info.stargazers_count + " Stars");
     console.log(info.forks_count + " Forks");
   }
@@ -384,7 +384,7 @@ default signing algorithm is
 ```js
 // OAuth1.0 - 3-legged server side flow (Twitter example)
 // step 1
-var qs = require('querystring')
+const qs = require('querystring')
   , oauth =
     { callback: 'http://mysite.com/callback/'
     , consumer_key: CONSUMER_KEY
@@ -399,14 +399,14 @@ request.post({url:url, oauth:oauth}, function (e, r, body) {
   // verified with twitter that they are authorizing your app.
 
   // step 2
-  var req_data = qs.parse(body)
-  var uri = 'https://api.twitter.com/oauth/authenticate'
+  const req_data = qs.parse(body)
+  const uri = 'https://api.twitter.com/oauth/authenticate'
     + '?' + qs.stringify({oauth_token: req_data.oauth_token})
   // redirect the user to the authorize uri
 
   // step 3
   // after the user is redirected back to your server
-  var auth_data = qs.parse(body)
+  const auth_data = qs.parse(body)
     , oauth =
       { consumer_key: CONSUMER_KEY
       , consumer_secret: CONSUMER_SECRET
@@ -418,7 +418,7 @@ request.post({url:url, oauth:oauth}, function (e, r, body) {
     ;
   request.post({url:url, oauth:oauth}, function (e, r, body) {
     // ready to make signed requests on behalf of the user
-    var perm_data = qs.parse(body)
+    const perm_data = qs.parse(body)
       , oauth =
         { consumer_key: CONSUMER_KEY
         , consumer_secret: CONSUMER_SECRET
@@ -607,14 +607,14 @@ TLS/SSL Protocol options, such as `cert`, `key` and `passphrase`, can be
 set directly in `options` object, in the `agentOptions` property of the `options` object, or even in `https.globalAgent.options`. Keep in mind that, although `agentOptions` allows for a slightly wider range of configurations, the recommended way is via `options` object directly, as using `agentOptions` or `https.globalAgent.options` would not be applied in the same way in proxied environments (as data travels through a TLS connection instead of an http/https agent).
 
 ```js
-var fs = require('fs')
+const fs = require('fs')
     , path = require('path')
     , certFile = path.resolve(__dirname, 'ssl/client.crt')
     , keyFile = path.resolve(__dirname, 'ssl/client.key')
     , caFile = path.resolve(__dirname, 'ssl/ca.cert.pem')
     , request = require('request');
 
-var options = {
+const options = {
     url: 'https://api.some-server.com/',
     cert: fs.readFileSync(certFile),
     key: fs.readFileSync(keyFile),
@@ -631,13 +631,13 @@ In the example below, we call an API that requires client side SSL certificate
 (in PEM format) with passphrase protected private key (in PEM format) and disable the SSLv3 protocol:
 
 ```js
-var fs = require('fs')
+const fs = require('fs')
     , path = require('path')
     , certFile = path.resolve(__dirname, 'ssl/client.crt')
     , keyFile = path.resolve(__dirname, 'ssl/client.key')
     , request = require('request');
 
-var options = {
+const options = {
     url: 'https://api.some-server.com/',
     agentOptions: {
         cert: fs.readFileSync(certFile),
@@ -708,7 +708,7 @@ The `options.har` property will override the values: `url`, `method`, `qs`, `hea
 A validation step will check if the HAR Request format matches the latest spec (v1.2) and will skip parsing if not matching.
 
 ```js
-  var request = require('request')
+  const request = require('request')
   request({
     // will be ignored
     method: 'GET',
@@ -902,13 +902,13 @@ instead, it **returns a wrapper** that has your default settings applied to it.
 For example:
 ```js
 //requests using baseRequest() will set the 'x-token' header
-var baseRequest = request.defaults({
+const baseRequest = request.defaults({
   headers: {'x-token': 'my-token'}
 })
 
 //requests using specialRequest() will include the 'x-token' header set in
 //baseRequest and will also include the 'special' header
-var specialRequest = baseRequest.defaults({
+const specialRequest = baseRequest.defaults({
   headers: {special: 'special value'}
 })
 ```
@@ -1008,7 +1008,7 @@ request.get('http://10.255.255.1', {timeout: 1500}, function(err) {
 ## Examples:
 
 ```js
-  var request = require('request')
+  const request = require('request')
     , rand = Math.floor(Math.random()*100000000).toString()
     ;
   request(
@@ -1039,7 +1039,7 @@ while the response object is unmodified and will contain compressed data if
 the server sent a compressed response.
 
 ```js
-  var request = require('request')
+  const request = require('request')
   request(
     { method: 'GET'
     , uri: 'http://www.google.com'
@@ -1067,7 +1067,7 @@ the server sent a compressed response.
 Cookies are disabled by default (else, they would be used in subsequent requests). To enable cookies, set `jar` to `true` (either in `defaults` or `options`).
 
 ```js
-var request = request.defaults({jar: true})
+const request = request.defaults({jar: true})
 request('http://www.google.com', function () {
   request('http://images.google.com')
 })
@@ -1076,8 +1076,8 @@ request('http://www.google.com', function () {
 To use a custom cookie jar (instead of `request`’s global cookie jar), set `jar` to an instance of `request.jar()` (either in `defaults` or `options`)
 
 ```js
-var j = request.jar()
-var request = request.defaults({jar:j})
+const j = request.jar()
+const request = request.defaults({jar:j})
 request('http://www.google.com', function () {
   request('http://images.google.com')
 })
@@ -1086,9 +1086,9 @@ request('http://www.google.com', function () {
 OR
 
 ```js
-var j = request.jar();
-var cookie = request.cookie('key1=value1');
-var url = 'http://www.google.com';
+const j = request.jar();
+const cookie = request.cookie('key1=value1');
+const url = 'http://www.google.com';
 j.setCookie(cookie, url);
 request({url: url, jar: j}, function () {
   request('http://images.google.com')
@@ -1101,9 +1101,9 @@ which supports saving to and restoring from JSON files), pass it as a parameter
 to `request.jar()`:
 
 ```js
-var FileCookieStore = require('tough-cookie-filestore');
+const FileCookieStore = require('tough-cookie-filestore');
 // NOTE - currently the 'cookies.json' file must already exist!
-var j = request.jar(new FileCookieStore('cookies.json'));
+const j = request.jar(new FileCookieStore('cookies.json'));
 request = request.defaults({ jar : j })
 request('http://www.google.com', function() {
   request('http://images.google.com')
@@ -1119,10 +1119,10 @@ for details.
 To inspect your cookie jar after a request:
 
 ```js
-var j = request.jar()
+const j = request.jar()
 request({url: 'http://www.google.com', jar: j}, function () {
-  var cookie_string = j.getCookieString(url); // "key1=value1; key2=value2; ..."
-  var cookies = j.getCookies(url);
+  const cookie_string = j.getCookieString(url); // "key1=value1; key2=value2; ..."
+  const cookies = j.getCookies(url);
   // [{key: 'key1', value: 'value1', domain: "www.google.com", ...}, ...]
 })
 ```