repl: refactor lib/repl.js

* remove unnecessary backslash (`\`) escaping in regular expressions
* favor `===` over `==`
* multiline arrays indentation consistent with other indentation

PR-URL: https://github.com/nodejs/node/pull/9374
Ref: https://github.com/nodejs/node/pull/9747
Reviewed-By: Rod Vagg <rod@vagg.org>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Roman Reiss <me@silverwind.io>

lib/repl.js

@@ -783,7 +783,7 @@ ArrayStream.prototype.writable = true;
 ArrayStream.prototype.resume = function() {};
 ArrayStream.prototype.write = function() {};
 
-const requireRE = /\brequire\s*\(['"](([\w\.\/-]+\/)?([\w\.\/-]*))/;
+const requireRE = /\brequire\s*\(['"](([\w./-]+\/)?([\w./-]*))/;
 const simpleExpressionRE =
     /(([a-zA-Z_$](?:\w|\$)*)\.)*([a-zA-Z_$](?:\w|\$)*)\.?$/;
 
@@ -1036,7 +1036,7 @@ function complete(line, callback) {
       var newCompletionGroups = [];
       for (i = 0; i < completionGroups.length; i++) {
         group = completionGroups[i].filter(function(elem) {
-          return elem.indexOf(filter) == 0;
+          return elem.indexOf(filter) === 0;
         });
         if (group.length) {
           newCompletionGroups.push(group);
@@ -1339,8 +1339,8 @@ function regexpEscape(s) {
  * @return {String} The converted command.
  */
 REPLServer.prototype.convertToContext = function(cmd) {
-  const scopeVar = /^\s*var\s*([_\w\$]+)(.*)$/m;
-  const scopeFunc = /^\s*function\s*([_\w\$]+)/;
+  const scopeVar = /^\s*var\s*([\w$]+)(.*)$/m;
+  const scopeFunc = /^\s*function\s*([\w$]+)/;
   var matches;
 
   // Replaces: var foo = "bar";  with: self.context.foo = bar;