doc: additional example edits

Additional example edits for consistency

Author: jasnell

Diff for: doc/api/child_process.markdown

@@ -166,8 +166,7 @@ a `'message'` event on the child.
 For example:
 
     const cp = require('child_process');
-
-    var n = cp.fork(`${__dirname}/sub.js`);
+    const n = cp.fork(`${__dirname}/sub.js`);
 
     n.on('message', (m) => {
       console.log('PARENT got message:', m);
@@ -215,7 +214,7 @@ Here is an example of sending a server:
     const child = require('child_process').fork('child.js');
 
     // Open up the server object and send the handle.
-    var server = require('net').createServer();
+    const server = require('net').createServer();
     server.on('connection', (socket) => {
       socket.end('handled by parent');
     });
@@ -251,7 +250,7 @@ process.
     const special = require('child_process').fork('child.js', ['special']);
 
     // Open up the server and send sockets to child
-    var server = require('net').createServer();
+    const server = require('net').createServer();
     server.on('connection', (socket) => {
 
       // if this is a VIP
@@ -320,7 +319,7 @@ the parent's `child.stdio[1]` is a stream, all other values in the array are
     const fs = require('fs');
     const child_process = require('child_process');
 
-    child = child_process.spawn('ls', {
+    const child = child_process.spawn('ls', {
         stdio: [
           0, // use parents stdin for child
           'pipe', // pipe child's stdout to parent
@@ -380,7 +379,7 @@ callback or returning an EventEmitter).
 Runs a command in a shell and buffers the output.
 
     const exec = require('child_process').exec;
-    var child = exec('cat *.js bad_file | wc -l',
+    const child = exec('cat *.js bad_file | wc -l',
       (error, stdout, stderr) => {
         console.log(`stdout: ${stdout}`);
         console.log(`stderr: ${stderr}`);
@@ -508,7 +507,7 @@ process, the default is `process.env`.
 Example of running `ls -lh /usr`, capturing `stdout`, `stderr`, and the exit code:
 
     const spawn = require('child_process').spawn;
-    var ls = spawn('ls', ['-lh', '/usr']);
+    const ls = spawn('ls', ['-lh', '/usr']);
 
     ls.stdout.on('data', (data) => {
       console.log(`stdout: ${data}`);
@@ -526,8 +525,8 @@ Example of running `ls -lh /usr`, capturing `stdout`, `stderr`, and the exit cod
 Example: A very elaborate way to run 'ps ax | grep ssh'
 
     const spawn = require('child_process').spawn;
-    var ps = spawn('ps', ['ax']);
-    var grep = spawn('grep', ['ssh']);
+    const ps = spawn('ps', ['ax']);
+    const grep = spawn('grep', ['ssh']);
 
     ps.stdout.on('data', (data) => {
       grep.stdin.write(data);
@@ -562,7 +561,7 @@ Example: A very elaborate way to run 'ps ax | grep ssh'
 Example of checking for failed exec:
 
     const spawn = require('child_process').spawn;
-    var child = spawn('bad_command');
+    const child = spawn('bad_command');
 
     child.on('error', (err) => {
       console.log('Failed to start child process.');
@@ -588,10 +587,10 @@ file:
 
      const fs = require('fs');
      const spawn = require('child_process').spawn;
-     var out = fs.openSync('./out.log', 'a');
-     var err = fs.openSync('./out.log', 'a');
+     const out = fs.openSync('./out.log', 'a');
+     const err = fs.openSync('./out.log', 'a');
 
-     var child = spawn('prg', [], {
+     const child = spawn('prg', [], {
        detached: true,
        stdio: [ 'ignore', out, err ]
      });

Diff for: doc/api/cluster.markdown

@@ -131,7 +131,7 @@ In a worker you can also use `process.on('error')`.
 
 Similar to the `cluster.on('exit')` event, but specific to this worker.
 
-    var worker = cluster.fork();
+    const worker = cluster.fork();
     worker.on('exit', (code, signal) => {
       if( signal ) {
         console.log(`worker was killed by signal: ${signal}`);
@@ -612,7 +612,7 @@ A reference to the current worker object. Not available in the master process.
       cluster.fork();
       cluster.fork();
     } else if (cluster.isWorker) {
-      console.log('I am worker #' + cluster.worker.id);
+      console.log(`I am worker #${cluster.worker.id}`);
     }
 
 ## cluster.workers

Diff for: doc/api/console.markdown

@@ -16,8 +16,8 @@ directly without `require`.
 
 Use `require('console').Console` or `console.Console` to access this class.
 
-    var Console = require('console').Console;
-    var Console = console.Console;
+    const Console = require('console').Console;
+    const Console = console.Console;
 
 You can use the `Console` class to create a simple logger like `console` but
 with different output streams.
@@ -29,10 +29,10 @@ Create a new `Console` by passing one or two writable stream instances.
 is used for warning or error output. If `stderr` isn't passed, the warning
 and error output will be sent to the `stdout`.
 
-    var output = fs.createWriteStream('./stdout.log');
-    var errorOutput = fs.createWriteStream('./stderr.log');
+    const output = fs.createWriteStream('./stdout.log');
+    const errorOutput = fs.createWriteStream('./stderr.log');
     // custom simple logger
-    var logger = new Console(output, errorOutput);
+    const logger = new Console(output, errorOutput);
     // use it like console
     var count = 5;
     logger.log('count: %d', count);

Diff for: doc/api/crypto.markdown

@@ -281,8 +281,8 @@ associated with the private key being set.
 Example (obtaining a shared secret):
 
     const crypto = require('crypto');
-    var alice = crypto.createECDH('secp256k1');
-    var bob = crypto.createECDH('secp256k1');
+    const alice = crypto.createECDH('secp256k1');
+    const bob = crypto.createECDH('secp256k1');
 
     // Note: This is a shortcut way to specify one of Alice's previous private
     // keys. It would be unwise to use such a predictable private key in a real
@@ -294,8 +294,8 @@ Example (obtaining a shared secret):
     // Bob uses a newly generated cryptographically strong pseudorandom key pair
     bob.generateKeys();
 
-    var alice_secret = alice.computeSecret(bob.getPublicKey(), null, 'hex');
-    var bob_secret = bob.computeSecret(alice.getPublicKey(), null, 'hex');
+    const alice_secret = alice.computeSecret(bob.getPublicKey(), null, 'hex');
+    const bob_secret = bob.computeSecret(alice.getPublicKey(), null, 'hex');
 
     // alice_secret and bob_secret should be the same shared secret value
     console.log(alice_secret === bob_secret);
@@ -535,13 +535,13 @@ algorithms.
 
 Example: this program that takes the sha256 sum of a file
 
-    var filename = process.argv[2];
+    const filename = process.argv[2];
     const crypto = require('crypto');
     const fs = require('fs');
 
-    var shasum = crypto.createHash('sha256');
+    const shasum = crypto.createHash('sha256');
 
-    var s = fs.ReadStream(filename);
+    const s = fs.ReadStream(filename);
     s.on('data', (d) => {
       shasum.update(d);
     });
@@ -581,7 +581,7 @@ Returns an array with the names of the supported ciphers.
 
 Example:
 
-    var ciphers = crypto.getCiphers();
+    const ciphers = crypto.getCiphers();
     console.log(ciphers); // ['aes-128-cbc', 'aes-128-ccm', ...]
 
 ## crypto.getCurves()
@@ -590,7 +590,7 @@ Returns an array with the names of the supported elliptic curves.
 
 Example:
 
-    var curves = crypto.getCurves();
+    const curves = crypto.getCurves();
     console.log(curves); // ['secp256k1', 'secp384r1', ...]
 
 ## crypto.getDiffieHellman(group_name)
@@ -609,14 +609,14 @@ and communication time.
 Example (obtaining a shared secret):
 
     const crypto = require('crypto');
-    var alice = crypto.getDiffieHellman('modp14');
-    var bob = crypto.getDiffieHellman('modp14');
+    const alice = crypto.getDiffieHellman('modp14');
+    const bob = crypto.getDiffieHellman('modp14');
 
     alice.generateKeys();
     bob.generateKeys();
 
-    var alice_secret = alice.computeSecret(bob.getPublicKey(), null, 'hex');
-    var bob_secret = bob.computeSecret(alice.getPublicKey(), null, 'hex');
+    const alice_secret = alice.computeSecret(bob.getPublicKey(), null, 'hex');
+    const bob_secret = bob.computeSecret(alice.getPublicKey(), null, 'hex');
 
     /* alice_secret and bob_secret should be the same */
     console.log(alice_secret == bob_secret);
@@ -627,7 +627,7 @@ Returns an array with the names of the supported hash algorithms.
 
 Example:
 
-    var hashes = crypto.getHashes();
+    const hashes = crypto.getHashes();
     console.log(hashes); // ['sha', 'sha1', 'sha1WithRSAEncryption', ...]
 
 ## crypto.pbkdf2(password, salt, iterations, keylen[, digest], callback)

Diff for: doc/api/debugger.markdown

@@ -27,9 +27,9 @@ For example, suppose `myscript.js` looked like this:
     x = 5;
     setTimeout(function () {
       debugger;
-      console.log("world");
+      console.log('world');
     }, 1000);
-    console.log("hello");
+    console.log('hello');
 
 Then once the debugger is run, it will break on line 4.
 
@@ -46,15 +46,15 @@ Then once the debugger is run, it will break on line 4.
       1 x = 5;
       2 setTimeout(function () {
       3   debugger;
-      4   console.log("world");
+      4   console.log('world');
       5 }, 1000);
     debug> next
     break in /home/indutny/Code/git/indutny/myscript.js:4
       2 setTimeout(function () {
       3   debugger;
-      4   console.log("world");
+      4   console.log('world');
       5 }, 1000);
-      6 console.log("hello");
+      6 console.log('hello');
     debug> repl
     Press Ctrl + C to leave debug repl
     > x
@@ -65,9 +65,9 @@ Then once the debugger is run, it will break on line 4.
     < world
     break in /home/indutny/Code/git/indutny/myscript.js:5
       3   debugger;
-      4   console.log("world");
+      4   console.log('world');
       5 }, 1000);
-      6 console.log("hello");
+      6 console.log('hello');
       7
     debug> quit
     %

Diff for: doc/api/dgram.markdown

@@ -9,13 +9,13 @@ Datagram sockets are available through `require('dgram')`.
 Important note: the behavior of [`dgram.Socket#bind()`][] has changed in v0.10
 and is always asynchronous now.  If you have code that looks like this:
 
-    var s = dgram.createSocket('udp4');
+    const s = dgram.createSocket('udp4');
     s.bind(1234);
     s.addMembership('224.0.0.114');
 
 You have to change it to this:
 
-    var s = dgram.createSocket('udp4');
+    const s = dgram.createSocket('udp4');
     s.bind(1234, () => {
       s.addMembership('224.0.0.114');
     });
@@ -94,7 +94,7 @@ Example of a UDP server listening on port 41234:
 
     const dgram = require('dgram');
 
-    var server = dgram.createSocket('udp4');
+    const server = dgram.createSocket('udp4');
 
     server.on('error', (err) => {
       console.log(`server error:\n${err.stack}`);
@@ -188,8 +188,8 @@ be calculated with respect to [byte length][] and not the character position.
 Example of sending a UDP packet to a random port on `localhost`;
 
     const dgram = require('dgram');
-    var message = new Buffer('Some bytes');
-    var client = dgram.createSocket('udp4');
+    const message = new Buffer('Some bytes');
+    const client = dgram.createSocket('udp4');
     client.send(message, 0, message.length, 41234, 'localhost', (err) => {
       client.close();
     });

Diff for: doc/api/domain.markdown

@@ -48,7 +48,7 @@ For example, this is not a good idea:
 // XXX WARNING!  BAD IDEA!
 
 var d = require('domain').create();
-d.on('error', function(er) {
+d.on('error', (er) => {
   // The error won't crash the process, but what it does is worse!
   // Though we've prevented abrupt process restarting, we are leaking
   // resources like crazy if this ever happens.
@@ -103,7 +103,7 @@ if (cluster.isMaster) {
   // See the cluster documentation for more details about using
   // worker processes to serve requests.  How it works, caveats, etc.
 
-  var server = require('http').createServer((req, res) => {
+  const server = require('http').createServer((req, res) => {
     var d = domain.create();
     d.on('error', (er) => {
       console.error('error', er.stack);
@@ -229,7 +229,9 @@ For example:
 
 ```
 // create a top-level domain for the server
-var serverDomain = domain.create();
+const domain = require('domain');
+const http = require('http');
+const serverDomain = domain.create();
 
 serverDomain.run(() => {
   // server is created in the scope of serverDomain
@@ -281,7 +283,9 @@ This is the most basic way to use a domain.
 Example:
 
 ```
-var d = domain.create();
+const domain = require('domain');
+const fs = require('fs');
+const d = domain.create();
 d.on('error', (er) => {
   console.error('Caught error!', er);
 });
@@ -341,7 +345,7 @@ thrown will be routed to the domain's `'error'` event.
 
 #### Example
 
-    var d = domain.create();
+    const d = domain.create();
 
     function readSomeFile(filename, cb) {
       fs.readFile(filename, 'utf8', d.bind(function(er, data) {
@@ -370,7 +374,7 @@ with a single error handler in a single place.
 
 #### Example
 
-    var d = domain.create();
+    const d = domain.create();
 
     function readSomeFile(filename, cb) {
       fs.readFile(filename, 'utf8', d.intercept(function(data) {

Diff for: doc/api/errors.markdown

@@ -49,7 +49,7 @@ employed appropriately or [`process.on('uncaughtException')`][] has a handler.
 ```javascript
 const net = require('net');
 
-var connection = net.connect('localhost');
+const connection = net.connect('localhost');
 
 // adding an 'error' event handler to a stream:
 connection.on('error', (err) => {
@@ -69,7 +69,7 @@ errors when no error handlers are attached. An example:
 ```javascript
 const EventEmitter = require('events');
 
-var ee = new EventEmitter();
+const ee = new EventEmitter();
 
 setImmediate(() => {
   // this will crash the process because no 'error' event