feat: repl to enter exec mode

Author: Jan Krems

lib/internal/inspect-repl.js

@@ -199,6 +199,7 @@ function createRepl(inspector) {
   let repl; // eslint-disable-line prefer-const
   let lastCommand;
 
+  const history = { control: [], debug: [] };
   const knownScripts = {};
   const watchedExpressions = [];
   const knownBreakpoints = [];
@@ -282,6 +283,27 @@ function createRepl(inspector) {
     return lastCommand;
   }
 
+  function evalInCurrentContext(code) {
+    // Repl asked for scope variables
+    if (code === '.scope') {
+      return Promise.reject('client.reqScopes not implemented');
+    }
+
+    if (selectedFrame) {
+      return Debugger.evaluateOnCallFrame({
+        callFrameId: selectedFrame.callFrameId,
+        expression: code,
+        objectGroup: 'node-inspect',
+        generatePreview: true,
+      }).then(convertResultToRemoteObject);
+    }
+    return Runtime.evaluate({
+      expression: code,
+      objectGroup: 'node-inspect',
+      generatePreview: true,
+    }).then(convertResultToRemoteObject);
+  }
+
   function controlEval(input, context, filename, callback) {
     debuglog('eval:', input);
     function returnToCallback(error, result) {
@@ -303,25 +325,24 @@ function createRepl(inspector) {
     }
   }
 
-  function debugEval(code) {
-    // Repl asked for scope variables
-    if (code === '.scope') {
-      return Promise.reject('client.reqScopes not implemented');
+  function debugEval(input, context, filename, callback) {
+    debuglog('eval:', input);
+    function returnToCallback(error, result) {
+      debuglog('end-eval:', input, error);
+      callback(error, result);
     }
 
-    if (selectedFrame) {
-      return Debugger.evaluateOnCallFrame({
-        callFrameId: selectedFrame.callFrameId,
-        expression: code,
-        objectGroup: 'node-inspect',
-        generatePreview: true,
-      }).then(convertResultToRemoteObject);
+    try {
+      const result = evalInCurrentContext(input);
+
+      if (result && typeof result.then === 'function') {
+        toCallback(result, returnToCallback);
+        return;
+      }
+      returnToCallback(null, result);
+    } catch (e) {
+      returnToCallback(e);
     }
-    return Runtime.evaluate({
-      expression: code,
-      objectGroup: 'node-inspect',
-      generatePreview: true,
-    }).then(convertResultToRemoteObject);
   }
 
   function formatWatchers(verbose = false) {
@@ -330,7 +351,7 @@ function createRepl(inspector) {
     }
 
     const inspectValue = expr =>
-      debugEval(expr)
+      evalInCurrentContext(expr)
         // .then(formatValue)
         .catch(error => `<${error.message}>`);
 
@@ -606,7 +627,7 @@ function createRepl(inspector) {
       },
 
       exec(expr) {
-        return debugEval(expr);
+        return evalInCurrentContext(expr);
       },
 
       get watchers() {
@@ -627,13 +648,12 @@ function createRepl(inspector) {
       },
 
       get repl() {
-        // if (!this.requireConnection()) return;
-        print('Press Ctrl + C to leave debug repl');
-
         // Don't display any default messages
         const listeners = repl.rli.listeners('SIGINT').slice(0);
         repl.rli.removeAllListeners('SIGINT');
 
+        const oldContext = repl.context;
+
         function exitDebugRepl() {
           // Restore all listeners
           process.nextTick(() => {
@@ -649,7 +669,7 @@ function createRepl(inspector) {
           history.debug = repl.rli.history;
           repl.rli.history = history.control;
 
-          repl.context = inspector.context;
+          repl.context = oldContext;
           repl.rli.setPrompt('debug> ');
           repl.displayPrompt();
 
@@ -664,16 +684,16 @@ function createRepl(inspector) {
         repl.on('exit', exitDebugRepl);
 
         // Set new
-        repl.eval = (code, evalCtx, file, cb) => {
-          toCallback(debugEval(code), cb);
-        };
+        repl.eval = debugEval;
         repl.context = {};
 
         // Swap history
         history.control = repl.rli.history;
         repl.rli.history = history.debug;
 
         repl.rli.setPrompt('> ');
+
+        print('Press Ctrl + C to leave debug repl');
         repl.displayPrompt();
       },
 
@@ -707,6 +727,12 @@ function createRepl(inspector) {
     repl = Repl.start(replOptions); // eslint-disable-line prefer-const
     initializeContext(repl.context);
     repl.on('reset', initializeContext);
+
+    repl.defineCommand('interrupt', () => {
+      // We want this for testing purposes where sending CTRL-C can be tricky.
+      repl.rli.emit('SIGINT');
+    });
+
     return repl;
   };
 }

test/cli/exec.test.js

@@ -17,6 +17,21 @@ test('examples/alive.js', (t) => {
     .then(() => {
       t.match(cli.output, '[ \'function\', \'function\' ]', 'works w/o paren');
     })
+    .then(() => cli.command('repl'))
+    .then(() => {
+      t.match(cli.output, 'Press Ctrl + C to leave debug repl\n> ',
+        'shows hint for how to leave repl');
+      t.notMatch(cli.output, 'debug>', 'changes the repl style');
+    })
+    .then(() => cli.command('[typeof heartbeat, typeof process.exit]'))
+    .then(() => cli.waitFor(/function/))
+    .then(() => cli.waitForPrompt())
+    .then(() => {
+      t.match(cli.output, '[ \'function\', \'function\' ]', 'can evaluate in the repl');
+      t.match(cli.output, /> $/);
+    })
+    .then(() => cli.ctrlC())
+    .then(() => cli.waitFor(/debug> $/))
     .then(() => cli.command('exec("[typeof heartbeat, typeof process.exit]")'))
     .then(() => {
       t.match(cli.output, '[ \'function\', \'function\' ]', 'works w/ paren');

test/cli/start-cli.js

@@ -73,7 +73,11 @@ function startCLI(args) {
     },
 
     waitForPrompt(timeout = 2000) {
-      return this.waitFor(/debug>\s*$/, timeout);
+      return this.waitFor(/>\s+$/, timeout);
+    },
+
+    ctrlC() {
+      return this.command('.interrupt');
     },
 
     get output() {