src: use internalBinding('config').hasInspector in JS land

Instead of `process.config.variables.v8_enable_inspector`
which depends on the variable name in gyp files, or detecting
`internalBinding('inspector').Connection`.
PR-URL: #25291
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: joyeecheung

lib/inspector.js

@@ -1,6 +1,5 @@
 'use strict';
 
-constEventEmitter=require('events');
 const{
 ERR_INSPECTOR_ALREADY_CONNECTED,
 ERR_INSPECTOR_CLOSED,
@@ -9,13 +8,16 @@ const {
 ERR_INVALID_ARG_TYPE,
 ERR_INVALID_CALLBACK
 }=require('internal/errors').codes;
+
+const{ hasInspector }=internalBinding('config');
+if(!hasInspector)
+thrownewERR_INSPECTOR_NOT_AVAILABLE();
+
+constEventEmitter=require('events');
 const{ validateString }=require('internal/validators');
 constutil=require('util');
 const{ Connection, open, url }=internalBinding('inspector');
 
-if(!Connection)
-thrownewERR_INSPECTOR_NOT_AVAILABLE();
-
 constconnectionSymbol=Symbol('connectionProperty');
 constmessageCallbacksSymbol=Symbol('messageCallbacks');
 constnextIdSymbol=Symbol('nextId');

lib/internal/bootstrap/cache.js

@@ -9,7 +9,7 @@ const { NativeModule } = require('internal/bootstrap/loaders');
 const{
  source, getCodeCache, compileFunction
 }=internalBinding('native_module');
-const{ hasTracing }=process.binding('config');
+const{ hasTracing, hasInspector}=process.binding('config');
 
 constdepsModule=Object.keys(source).filter(
 (key)=>NativeModule.isDepsModule(key)||key.startsWith('internal/deps')
@@ -33,7 +33,7 @@ const cannotUseCache = [
 
 // Skip modules that cannot be required when they are not
 // built into the binary.
-if(process.config.variables.v8_enable_inspector!==1){
+if(!hasInspector){
 cannotUseCache.push(
 'inspector',
 'internal/util/inspector',

lib/internal/bootstrap/node.js

@@ -19,6 +19,7 @@
 const{ internalBinding, NativeModule }=loaderExports;
 
 const{ getOptionValue }=NativeModule.require('internal/options');
+constconfig=internalBinding('config');
 
 functionstartup(){
 setupTraceCategoryState();
@@ -156,7 +157,7 @@ function startup() {
 NativeModule.require('internal/process/coverage').setupExitHooks();
 }
 
-if(process.config.variables.v8_enable_inspector){
+if(config.hasInspector){
 NativeModule.require('internal/inspector_async_hook').setup();
 }
 
@@ -296,7 +297,7 @@ function startup() {
 
 // TODO(joyeecheung): this property has not been well-maintained, should we
 // deprecate it in favor of a better API?
-const{ isDebugBuild, hasOpenSSL }=internalBinding('config');
+const{ isDebugBuild, hasOpenSSL }=config;
 Object.defineProperty(process,'features',{
 enumerable: true,
 writable: false,
@@ -636,7 +637,7 @@ function setupGlobalConsole() {
 writable: true
 });
 // TODO(joyeecheung): can we skip this if inspector is not active?
-if(process.config.variables.v8_enable_inspector){
+if(config.hasInspector){
 constinspector=
 NativeModule.require('internal/console/inspector');
 inspector.addInspectorApis(consoleFromNode,consoleFromVM);

lib/internal/process/coverage.js

@@ -51,12 +51,13 @@ function disableAllAsyncHooks() {
 exports.writeCoverage=writeCoverage;
 
 functionsetup(){
-const{Connection}=internalBinding('inspector');
-if(!Connection){
+const{hasInspector}=internalBinding('config');
+if(!hasInspector){
 process._rawDebug('inspector not enabled');
 return;
 }
 
+const{ Connection }=internalBinding('inspector');
 coverageConnection=newConnection((res)=>{
 if(coverageConnection._coverageCallback){
 coverageConnection._coverageCallback(res);

lib/internal/util/inspector.js

@@ -1,6 +1,6 @@
 'use strict';
 
-consthasInspector=process.config.variables.v8_enable_inspector===1;
+const{hasInspector }=internalBinding('config');
 constinspector=hasInspector ? require('inspector') : undefined;
 
 letsession;

src/node_config.cc

@@ -57,6 +57,12 @@ static void Initialize(Local<Object> target,
 READONLY_TRUE_PROPERTY(target, "hasTracing");
 #endif
 
+#if HAVE_INSPECTOR
+READONLY_TRUE_PROPERTY(target, "hasInspector");
+#else
+READONLY_FALSE_PROPERTY(target, "hasInspector");
+#endif
+
 #if !defined(NODE_WITHOUT_NODE_OPTIONS)
 READONLY_TRUE_PROPERTY(target, "hasNodeOptions");
 #endif