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 +734,35 @@
           "type": "boolean"
         }
       }
+    },
+    "watch": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "watch": {
+          "type": "boolean"
+        },
+        "watch-kill-signal": {
+          "type": "string"
+        },
+        "watch-path": {
+          "oneOf": [
+            {
+              "type": "string"
+            },
+            {
+              "items": {
+                "type": "string",
+                "minItems": 1
+              },
+              "type": "array"
+            }
+          ]
+        },
+        "watch-preserve-output": {
+          "type": "boolean"
+        }
+      }
     }
   },
   "type": "object"

lib/internal/main/watch_mode.js

@@ -17,7 +17,7 @@ const {
   triggerUncaughtException,
   exitCodes: { kNoFailure },
 } = internalBinding('errors');
-const { getOptionValue } = require('internal/options');
+const { getOptionValue, getOptionsAsFlagsFromBinding } = require('internal/options');
 const { FilesWatcher } = require('internal/watch_mode/files_watcher');
 const { green, blue, red, white, clear } = require('internal/util/colors');
 const { convertToValidSignal } = require('internal/util');
@@ -40,14 +40,14 @@ const kCommand = ArrayPrototypeSlice(process.argv, 1);
 const kCommandStr = inspect(ArrayPrototypeJoin(kCommand, ' '));
 
 const argsWithoutWatchOptions = [];
-
-for (let i = 0; i < process.execArgv.length; i++) {
-  const arg = process.execArgv[i];
+const argsFromBinding = getOptionsAsFlagsFromBinding();
+for (let i = 0; i < argsFromBinding.length; i++) {
+  const arg = argsFromBinding[i];
   if (StringPrototypeStartsWith(arg, '--watch=')) {
     continue;
   }
   if (arg === '--watch') {
-    const nextArg = process.execArgv[i + 1];
+    const nextArg = argsFromBinding[i + 1];
     if (nextArg && nextArg[0] !== '-') {
       // If `--watch` doesn't include `=` and the next
       // argument is not a flag then it is interpreted as
@@ -66,6 +66,16 @@ for (let i = 0; i < process.execArgv.length; i++) {
     }
     continue;
   }
+  if (StringPrototypeStartsWith(arg, '--experimental-config-file')) {
+    if (!arg.includes('=')) {
+      // Skip the flag and the next argument (the config file path)
+      i++;
+    }
+    continue;
+  }
+  if (arg === '--experimental-default-config-file') {
+    continue;
+  }
   ArrayPrototypePush(argsWithoutWatchOptions, arg);
 }
 

src/node_options.cc

@@ -242,7 +242,7 @@ 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) {
       errors->push_back("--watch requires specifying a file");
     }
 
@@ -1013,20 +1013,26 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
   AddOption("--watch",
             "run in watch mode",
             &EnvironmentOptions::watch_mode,
-            kAllowedInEnvvar);
+            kAllowedInEnvvar,
+            false,
+            OptionNamespaces::kWatchNamespace);
   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,

test/sequential/test-watch-mode.mjs

@@ -791,4 +791,73 @@ process.on('message', (message) => {
       `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
     ]);
   });
+
+  it('should watch changes to a file from config file', async () => {
+    const file = createTmpFile();
+    const configFile = createTmpFile(JSON.stringify({ watch: { 'watch': true } }), '.json');
+    const { stderr, stdout } = await runWriteSucceed({
+      file, watchedFile: file, args: ['--experimental-config-file', configFile, file], options: {
+        timeout: 10000
+      }
+    });
+
+    assert.strictEqual(stderr, '');
+    assert.deepStrictEqual(stdout, [
+      'running',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+      `Restarting ${inspect(file)}`,
+      'running',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+    ]);
+  });
+
+  it('should watch changes to a file with watch-path from config file', {
+    skip: !supportsRecursive,
+  }, async () => {
+    const dir = tmpdir.resolve('subdir4');
+    mkdirSync(dir);
+    const file = createTmpFile();
+    const watchedFile = createTmpFile('', '.js', dir);
+    const configFile = createTmpFile(JSON.stringify({ watch: { 'watch-path': [dir] } }), '.json', dir);
+
+    const args = ['--experimental-config-file', configFile, file];
+    const { stderr, stdout } = await runWriteSucceed({ file, watchedFile, args });
+
+    assert.strictEqual(stderr, '');
+    assert.deepStrictEqual(stdout, [
+      'running',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+      `Restarting ${inspect(file)}`,
+      'running',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+    ]);
+    assert.strictEqual(stderr, '');
+  });
+
+  it('should watch changes to a file from default config file', async () => {
+    const dir = tmpdir.resolve('subdir5');
+    mkdirSync(dir);
+
+    const file = createTmpFile('console.log("running");', '.js', dir);
+    writeFileSync(path.join(dir, 'node.config.json'), JSON.stringify({ watch: { 'watch': true } }));
+
+    const { stderr, stdout } = await runWriteSucceed({
+      file,
+      watchedFile: file,
+      args: ['--experimental-default-config-file', file],
+      options: {
+        timeout: 10000,
+        cwd: dir
+      }
+    });
+
+    assert.strictEqual(stderr, '');
+    assert.deepStrictEqual(stdout, [
+      'running',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+      `Restarting ${inspect(file)}`,
+      'running',
+      `Completed running ${inspect(file)}. Waiting for file changes before restarting...`,
+    ]);
+  });
 });