lib: add api to detect whether source-maps are enabled

doc/api/process.md

@@ -3517,6 +3517,19 @@ throw an error.
 Using this function is mutually exclusive with using the deprecated
 [`domain`][] built-in module.
 
+## `process.sourceMapsEnabled`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+> Stability: 1 - Experimental
+
+* {boolean}
+
+The `process.sourceMapsEnabled` property returns whether the
+[Source Map v3][Source Map] support for stack traces is enabled.
+
 ## `process.stderr`
 
 * {Stream}

lib/internal/bootstrap/node.js

@@ -326,13 +326,22 @@ process.emitWarning = emitWarning;
 
 {
   const {
+    getSourceMapsEnabled,
     setSourceMapsEnabled,
     maybeCacheGeneratedSourceMap,
   } = require('internal/source_map/source_map_cache');
   const {
     setMaybeCacheGeneratedSourceMap,
   } = internalBinding('errors');
 
+  ObjectDefineProperty(process, 'sourceMapsEnabled', {
+    __proto__: null,
+    enumerable: true,
+    configurable: true,
+    get() {
+      return getSourceMapsEnabled();
+    },
+  });
   process.setSourceMapsEnabled = setSourceMapsEnabled;
   // The C++ land calls back to maybeCacheGeneratedSourceMap()
   // when code is generated by user with eval() or new Function()

test/fixtures/source-map/output/source_map_disabled_by_api.js

@@ -2,9 +2,12 @@
 
 'use strict';
 require('../../../common');
+const assert = require('assert');
 Error.stackTraceLimit = 5;
 
+assert.strictEqual(process.sourceMapsEnabled, true);
 process.setSourceMapsEnabled(false);
+assert.strictEqual(process.sourceMapsEnabled, false);
 
 try {
   require('../enclosing-call-site-min.js');
@@ -17,6 +20,7 @@ delete require.cache[require
 
 // Re-enable.
 process.setSourceMapsEnabled(true);
+assert.strictEqual(process.sourceMapsEnabled, true);
 
 try {
   require('../enclosing-call-site-min.js');

test/fixtures/source-map/output/source_map_enabled_by_api.js

@@ -1,8 +1,11 @@
 'use strict';
 require('../../../common');
+const assert = require('assert');
 Error.stackTraceLimit = 5;
 
+assert.strictEqual(process.sourceMapsEnabled, false);
 process.setSourceMapsEnabled(true);
+assert.strictEqual(process.sourceMapsEnabled, true);
 
 try {
   require('../enclosing-call-site-min.js');
@@ -14,6 +17,7 @@ delete require.cache[require
   .resolve('../enclosing-call-site-min.js')];
 
 process.setSourceMapsEnabled(false);
+assert.strictEqual(process.sourceMapsEnabled, false);
 
 try {
   require('../enclosing-call-site-min.js');