src: add watch config namespace

Author: marco-ippolito

doc/api/cli.md

@@ -1022,6 +1022,9 @@ in the `$schema` must be replaced with the version of Node.js you are using.
   },
   "testRunner": {
     "test-isolation": "process"
+  },
+  "watch": {
+    "watch-preserve-output": true
   }
 }
 ```

doc/node-config-schema.json

@@ -734,6 +734,32 @@
           "type": "boolean"
         }
       }
+    },
+    "watch": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "watch-kill-signal": {
+          "type": "string"
+        },
+        "watch-path": {
+          "oneOf": [
+            {
+              "type": "string"
+            },
+            {
+              "items": {
+                "type": "string",
+                "minItems": 1
+              },
+              "type": "array"
+            }
+          ]
+        },
+        "watch-preserve-output": {
+          "type": "boolean"
+        }
+      }
     }
   },
   "type": "object"

src/node_options.cc

@@ -242,7 +242,8 @@ void EnvironmentOptions::CheckOptions(std::vector<std::string>* errors,
     } else if (test_runner_force_exit) {
       errors->push_back("either --watch or --test-force-exit "
                         "can be used, not both");
-    } else if (!test_runner && (argv->size() < 1 || (*argv)[1].empty())) {
+    } else if (!test_runner && watch_mode_paths.empty() &&
+               (argv->size() < 1 || (*argv)[1].empty())) {
       errors->push_back("--watch requires specifying a file");
     }
 
@@ -1017,16 +1018,20 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
   AddOption("--watch-path",
             "path to watch",
             &EnvironmentOptions::watch_mode_paths,
-            kAllowedInEnvvar);
+            kAllowedInEnvvar,
+            OptionNamespaces::kWatchNamespace);
   AddOption("--watch-kill-signal",
             "kill signal to send to the process on watch mode restarts"
             "(default: SIGTERM)",
             &EnvironmentOptions::watch_mode_kill_signal,
-            kAllowedInEnvvar);
+            kAllowedInEnvvar,
+            OptionNamespaces::kWatchNamespace);
   AddOption("--watch-preserve-output",
             "preserve outputs on watch mode restart",
             &EnvironmentOptions::watch_mode_preserve_output,
-            kAllowedInEnvvar);
+            kAllowedInEnvvar,
+            false,
+            OptionNamespaces::kWatchNamespace);
   Implies("--watch-path", "--watch");
   AddOption("--check",
             "syntax check script without executing",

src/node_options.h

@@ -415,7 +415,8 @@ std::vector<std::string> MapAvailableNamespaces();
 // Define all namespace entries
 #define OPTION_NAMESPACE_LIST(V)                                               \
   V(kNoNamespace, "")                                                          \
-  V(kTestRunnerNamespace, "testRunner")
+  V(kTestRunnerNamespace, "testRunner")                                        \
+  V(kWatchNamespace, "watch")
 
 enum class OptionNamespaces {
 #define V(name, _) name,