debugger: remove variable redeclarations

Some variables are declared with var more than once in the same scope.
This change reduces the declarations to one per scope.

PR-URL: #4633
Reviewed-By: jasnell - James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

lib/_debugger.js

@@ -462,7 +462,7 @@ Client.prototype.setBreakpoint = function(req, cb) {
 };
 
 Client.prototype.clearBreakpoint = function(req, cb) {
-  var req = {
+  req = {
     command: 'clearbreakpoint',
     arguments: req
   };
@@ -1352,9 +1352,10 @@ Interface.prototype.setBreakpoint = function(script, line,
     return;
   }
 
+  let req;
   if (/\(\)$/.test(script)) {
     // setBreakpoint('functionname()');
-    var req = {
+    req = {
       type: 'function',
       target: script.replace(/\(\)$/, ''),
       condition: condition
@@ -1380,7 +1381,6 @@ Interface.prototype.setBreakpoint = function(script, line,
     if (ambiguous) return this.error('Script name is ambiguous');
     if (line <= 0) return this.error('Line should be a positive value');
 
-    var req;
     if (scriptId) {
       req = {
         type: 'scriptId',
@@ -1651,7 +1651,7 @@ Interface.prototype.trySpawn = function(cb) {
 
   var isRemote = false;
   if (this.args.length === 2) {
-    var match = this.args[1].match(/^([^:]+):(\d+)$/);
+    const match = this.args[1].match(/^([^:]+):(\d+)$/);
 
     if (match) {
       // Connecting to remote debugger
@@ -1675,7 +1675,7 @@ Interface.prototype.trySpawn = function(cb) {
       }
       isRemote = true;
     } else {
-      var match = this.args[1].match(/^--port=(\d+)$/);
+      const match = this.args[1].match(/^--port=(\d+)$/);
       if (match) {
         // Start debugger on custom port
         // `node debug --port=5858 app.js`