feat: exec .scope

Author: Jan Krems

lib/internal/inspect-repl.js

@@ -168,6 +168,13 @@ class RemoteObject {
       case 'symbol':
         return opts.stylize(this.description, 'special');
 
+      case 'function': {
+        const fnNameMatch = (this.description).match(/^(?:function\*? )?([^(\s]+)\(/);
+        const fnName = fnNameMatch ? `: ${fnNameMatch[1]}` : '';
+        const formatted = `[${this.className}${fnName}]`;
+        return opts.stylize(formatted, 'special');
+      }
+
       case 'object':
         switch (this.subtype) {
           case 'date':
@@ -286,10 +293,43 @@ function createRepl(inspector) {
     return formatScripts();
   };
 
+  class ScopeSnapshot {
+    constructor(scope, properties) {
+      Object.assign(this, scope);
+      this.properties = new Map(properties.map((prop) => {
+        // console.error(prop);
+        const value = new RemoteObject(prop.value);
+        return [prop.name, value];
+      }));
+    }
+
+    [util.inspect.custom](depth, opts) {
+      const type = `${this.type[0].toUpperCase()}${this.type.slice(1)}`;
+      const name = this.name ? `<${this.name}>` : '';
+      const prefix = `${type}${name} `;
+      return util.inspect(this.properties, opts)
+        .replace(/^Map /, prefix);
+    }
+  }
+
   class CallFrame {
     constructor(callFrame) {
       Object.assign(this, callFrame);
     }
+
+    loadScopes() {
+      return Promise.all(
+        this.scopeChain
+          .filter((scope) => scope.type !== 'global')
+          .map((scope) => {
+            const { objectId } = scope.object;
+            return Runtime.getProperties({
+              objectId,
+              generatePreview: true,
+            }).then(({ result }) => new ScopeSnapshot(scope, result));
+          })
+      );
+    }
   }
 
   class Backtrace extends Array {
@@ -328,7 +368,10 @@ function createRepl(inspector) {
   function evalInCurrentContext(code) {
     // Repl asked for scope variables
     if (code === '.scope') {
-      return Promise.reject('client.reqScopes not implemented');
+      if (!selectedFrame) {
+        return Promise.reject(new Error('Requires execution to be paused'));
+      }
+      return selectedFrame.loadScopes();
     }
 
     if (selectedFrame) {

test/cli/exec.test.js

@@ -45,3 +45,25 @@ test('examples/alive.js', (t) => {
     .then(() => cli.quit())
     .then(null, onFatal);
 });
+
+test('exec .scope', (t) => {
+  const cli = startCLI(['examples/backtrace.js']);
+
+  function onFatal(error) {
+    cli.quit();
+    throw error;
+  }
+
+  return cli.waitFor(/break/)
+    .then(() => cli.waitForPrompt())
+    .then(() => cli.stepCommand('c'))
+    .then(() => cli.command('exec .scope'))
+    .then(() => {
+      t.match(cli.output, '\'moduleScoped\'', 'displays closure from module body');
+      t.match(cli.output, '\'a\'', 'displays local / function arg');
+      t.match(cli.output, '\'l1\'', 'displays local scope');
+      t.notMatch(cli.output, '\'encodeURIComponent\'', 'omits global scope');
+    })
+    .then(() => cli.quit())
+    .then(null, onFatal);
+});