tools: new eslint rules

.eslintrc.js

@@ -130,6 +130,7 @@ module.exports = {
     // http://eslint.org/docs/rules/#variables
     'no-delete-var': 'error',
     'no-undef': 'error',
+    'no-undef-init': 'error',
     'no-unused-vars': ['error', { args: 'none' }],
     'no-use-before-define': ['error', {
       classes: true,
@@ -165,7 +166,7 @@ module.exports = {
       ObjectExpression: 'first',
       SwitchCase: 1,
     }],
-    'key-spacing': ['error', { mode: 'minimum' }],
+    'key-spacing': ['error', { mode: 'strict' }],
     'keyword-spacing': 'error',
     'linebreak-style': ['error', 'unix'],
     'max-len': ['error', {
@@ -211,10 +212,12 @@ module.exports = {
     'no-tabs': 'error',
     'no-trailing-spaces': 'error',
     'no-unsafe-finally': 'error',
+    'no-whitespace-before-property': 'error',
     'object-curly-spacing': ['error', 'always'],
+    'one-var': ['error', { initialized: 'never' }],
     'one-var-declaration-per-line': 'error',
     'operator-linebreak': ['error', 'after'],
-    quotes: ['error', 'single', 'avoid-escape'],
+    quotes: ['error', 'single', { avoidEscape: true }],
     semi: 'error',
     'semi-spacing': 'error',
     'space-before-blocks': ['error', 'always'],

benchmark/http/_chunky_http_client.js

@@ -5,8 +5,8 @@ const common = require('../common.js');
 const net = require('net');
 
 const bench = common.createBenchmark(main, {
-  len:  [1, 4, 8, 16, 32, 64, 128],
-  n:  [5, 50, 500, 2000],
+  len: [1, 4, 8, 16, 32, 64, 128],
+  n: [5, 50, 500, 2000],
   type: ['send'],
 });
 

benchmark/tls/tls-connect.js

@@ -1,7 +1,7 @@
 'use strict';
-var fs = require('fs'),
-  path = require('path'),
-  tls = require('tls');
+const fs = require('fs');
+const path = require('path');
+const tls = require('tls');
 
 const common = require('../common.js');
 const bench = common.createBenchmark(main, {

doc/.eslintrc.yaml

@@ -12,6 +12,7 @@ rules:
   no-var: error
   prefer-const: error
   prefer-rest-params: error
+  prefer-template: error
 
   # Stylistic Issues
   no-multiple-empty-lines: [error, {max: 1, maxEOF: 0, maxBOF: 0}]

doc/api/esm.md

@@ -118,7 +118,7 @@ given module specifier and parent file URL:
 
 ```js
 const baseURL = new URL('file://');
-baseURL.pathname = process.cwd() + '/';
+baseURL.pathname = `${process.cwd()}/`;
 
 export async function resolve(specifier,
                               parentModuleURL = baseURL,
@@ -161,7 +161,7 @@ const builtins = Module.builtinModules;
 const JS_EXTENSIONS = new Set(['.js', '.mjs']);
 
 const baseURL = new URL('file://');
-baseURL.pathname = process.cwd() + '/';
+baseURL.pathname = `${process.cwd()}/`;
 
 export function resolve(specifier, parentModuleURL = baseURL, defaultResolve) {
   if (builtins.includes(specifier)) {

doc/api/http.md

@@ -422,7 +422,7 @@ const req = http.request(options);
 req.end();
 
 req.on('information', (res) => {
-  console.log('got information prior to main response: ' + res.statusCode);
+  console.log(`Got information prior to main response: ${res.statusCode}`);
 });
 ```
 

doc/api/stream.md

@@ -1852,7 +1852,7 @@ class Counter extends Readable {
     if (i > this._max)
       this.push(null);
     else {
-      const str = '' + i;
+      const str = String(i);
       const buf = Buffer.from(str, 'ascii');
       this.push(buf);
     }

lib/internal/util.js

@@ -228,8 +228,8 @@ function getSystemErrorName(err) {
 // getConstructorOf is wrapped into this to save iterations
 function getIdentificationOf(obj) {
   const original = obj;
-  let constructor = undefined;
-  let tag = undefined;
+  let constructor;
+  let tag;
 
   while (obj) {
     if (constructor === undefined) {

test/parallel/test-cluster-worker-kill.js

@@ -40,29 +40,28 @@ if (cluster.isWorker) {
 
 } else if (cluster.isMaster) {
 
-  const KILL_SIGNAL = 'SIGKILL',
-    expected_results = {
-      cluster_emitDisconnect: [1, "the cluster did not emit 'disconnect'"],
-      cluster_emitExit: [1, "the cluster did not emit 'exit'"],
-      cluster_exitCode: [null, 'the cluster exited w/ incorrect exitCode'],
-      cluster_signalCode: [KILL_SIGNAL,
-                           'the cluster exited w/ incorrect signalCode'],
-      worker_emitDisconnect: [1, "the worker did not emit 'disconnect'"],
-      worker_emitExit: [1, "the worker did not emit 'exit'"],
-      worker_state: ['disconnected', 'the worker state is incorrect'],
-      worker_exitedAfter: [false,
-                           'the .exitedAfterDisconnect flag is incorrect'],
-      worker_died: [true, 'the worker is still running'],
-      worker_exitCode: [null, 'the worker exited w/ incorrect exitCode'],
-      worker_signalCode: [KILL_SIGNAL,
-                          'the worker exited w/ incorrect signalCode']
-    },
-    results = {
-      cluster_emitDisconnect: 0,
-      cluster_emitExit: 0,
-      worker_emitDisconnect: 0,
-      worker_emitExit: 0
-    };
+  const KILL_SIGNAL = 'SIGKILL';
+  const expected_results = {
+    cluster_emitDisconnect: [1, "the cluster did not emit 'disconnect'"],
+    cluster_emitExit: [1, "the cluster did not emit 'exit'"],
+    cluster_exitCode: [null, 'the cluster exited w/ incorrect exitCode'],
+    cluster_signalCode: [KILL_SIGNAL,
+                         'the cluster exited w/ incorrect signalCode'],
+    worker_emitDisconnect: [1, "the worker did not emit 'disconnect'"],
+    worker_emitExit: [1, "the worker did not emit 'exit'"],
+    worker_state: ['disconnected', 'the worker state is incorrect'],
+    worker_exitedAfter: [false, 'the .exitedAfterDisconnect flag is incorrect'],
+    worker_died: [true, 'the worker is still running'],
+    worker_exitCode: [null, 'the worker exited w/ incorrect exitCode'],
+    worker_signalCode: [KILL_SIGNAL,
+                        'the worker exited w/ incorrect signalCode']
+  };
+  const results = {
+    cluster_emitDisconnect: 0,
+    cluster_emitExit: 0,
+    worker_emitDisconnect: 0,
+    worker_emitExit: 0
+  };
 
 
   // start worker

test/parallel/test-eslint-require-buffer.js

@@ -36,14 +36,14 @@ ruleTester.run('require-buffer', rule, {
       output: useStrict + bufferModule + useBuffer,
     },
     {
-      code:  mockComment + useBuffer,
+      code: mockComment + useBuffer,
       errors: [{ message }],
-      output:  mockComment + bufferModule + useBuffer,
+      output: mockComment + bufferModule + useBuffer,
     },
     {
-      code:  mockComment + useStrict + useBuffer,
+      code: mockComment + useStrict + useBuffer,
       errors: [{ message }],
-      output:  mockComment + useStrict + bufferModule + useBuffer,
+      output: mockComment + useStrict + bufferModule + useBuffer,
     },
   ]
 });

test/parallel/test-fs-utimes.js

@@ -88,7 +88,7 @@ function testIt(atime, mtime, callback) {
       expect_errno('futimesSync', fd, ex, 'ENOSYS');
     }
 
-    let err = undefined;
+    let err;
     try {
       fs.utimesSync('foobarbaz', atime, mtime);
     } catch (ex) {

test/parallel/test-https-agent-servername.js

@@ -10,7 +10,7 @@ const fixtures = require('../common/fixtures');
 const options = {
   key: fixtures.readKey('agent1-key.pem'),
   cert: fixtures.readKey('agent1-cert.pem'),
-  ca:  fixtures.readKey('ca1-cert.pem')
+  ca: fixtures.readKey('ca1-cert.pem')
 };