test: refactor test-crypto-cipheriv-decipheriv

Make change in test file from var to const/let.

PR-URL: https://github.com/nodejs/node/pull/10018
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

test/parallel/test-crypto-cipheriv-decipheriv.js

@@ -1,25 +1,25 @@
 'use strict';
-var common = require('../common');
-var assert = require('assert');
+const common = require('../common');
+const assert = require('assert');
 
 if (!common.hasCrypto) {
   common.skip('missing crypto');
   return;
 }
-var crypto = require('crypto');
+const crypto = require('crypto');
 
 function testCipher1(key, iv) {
   // Test encyrption and decryption with explicit key and iv
-  var plaintext =
+  const plaintext =
           '32|RmVZZkFUVmpRRkp0TmJaUm56ZU9qcnJkaXNNWVNpTTU*|iXmckfRWZBGWWELw' +
           'eCBsThSsfUHLeRe0KCsK8ooHgxie0zOINpXxfZi/oNG7uq9JWFVCk70gfzQH8ZUJ' +
           'jAfaFg**';
-  var cipher = crypto.createCipheriv('des-ede3-cbc', key, iv);
-  var ciph = cipher.update(plaintext, 'utf8', 'hex');
+  const cipher = crypto.createCipheriv('des-ede3-cbc', key, iv);
+  let ciph = cipher.update(plaintext, 'utf8', 'hex');
   ciph += cipher.final('hex');
 
-  var decipher = crypto.createDecipheriv('des-ede3-cbc', key, iv);
-  var txt = decipher.update(ciph, 'hex', 'utf8');
+  const decipher = crypto.createDecipheriv('des-ede3-cbc', key, iv);
+  let txt = decipher.update(ciph, 'hex', 'utf8');
   txt += decipher.final('utf8');
 
   assert.strictEqual(txt, plaintext, 'encryption/decryption with key and iv');
@@ -28,11 +28,11 @@ function testCipher1(key, iv) {
   // NB: In real life, it's not guaranteed that you can get all of it
   // in a single read() like this.  But in this case, we know it's
   // quite small, so there's no harm.
-  var cStream = crypto.createCipheriv('des-ede3-cbc', key, iv);
+  const cStream = crypto.createCipheriv('des-ede3-cbc', key, iv);
   cStream.end(plaintext);
   ciph = cStream.read();
 
-  var dStream = crypto.createDecipheriv('des-ede3-cbc', key, iv);
+  const dStream = crypto.createDecipheriv('des-ede3-cbc', key, iv);
   dStream.end(ciph);
   txt = dStream.read().toString('utf8');
 
@@ -42,16 +42,16 @@ function testCipher1(key, iv) {
 
 function testCipher2(key, iv) {
   // Test encyrption and decryption with explicit key and iv
-  var plaintext =
+  const plaintext =
           '32|RmVZZkFUVmpRRkp0TmJaUm56ZU9qcnJkaXNNWVNpTTU*|iXmckfRWZBGWWELw' +
           'eCBsThSsfUHLeRe0KCsK8ooHgxie0zOINpXxfZi/oNG7uq9JWFVCk70gfzQH8ZUJ' +
           'jAfaFg**';
-  var cipher = crypto.createCipheriv('des-ede3-cbc', key, iv);
-  var ciph = cipher.update(plaintext, 'utf8', 'buffer');
+  const cipher = crypto.createCipheriv('des-ede3-cbc', key, iv);
+  let ciph = cipher.update(plaintext, 'utf8', 'buffer');
   ciph = Buffer.concat([ciph, cipher.final('buffer')]);
 
-  var decipher = crypto.createDecipheriv('des-ede3-cbc', key, iv);
-  var txt = decipher.update(ciph, 'buffer', 'utf8');
+  const decipher = crypto.createDecipheriv('des-ede3-cbc', key, iv);
+  let txt = decipher.update(ciph, 'buffer', 'utf8');
   txt += decipher.final('utf8');
 
   assert.strictEqual(txt, plaintext, 'encryption/decryption with key and iv');