repl: add colors for uncaught exceptions and use a better indicator

This switches "Thrown:" with "Uncaught" to outline clearer that the thrown error is not caught. It will also mark the error in red in case the terminal supports colors / if colors are activated for the repl.
nodejs · BridgeAR · Sep 23, 2019 · Nov 26, 2019 · Nov 26, 2019 · 1a7de3404c1c5f3ac11edb6a543b7ef5a3874eed
commit 1a7de3404c1c5f3ac11edb6a543b7ef5a3874eed
diff --git a/lib/internal/util/inspect.js b/lib/internal/util/inspect.js
@@ -257,6 +257,7 @@ ObjectDefineProperty(inspect, 'defaultOptions', {
   }
 });
 
+// TODO(BridgeAR): Add further color codes.
 // http://en.wikipedia.org/wiki/ANSI_escape_code#graphics
 inspect.colors = ObjectAssign(ObjectCreate(null), {
   bold: [1, 22],
@@ -271,7 +272,8 @@ inspect.colors = ObjectAssign(ObjectCreate(null), {
   green: [32, 39],
   magenta: [35, 39],
   red: [31, 39],
-  yellow: [33, 39]
+  yellow: [33, 39],
+  brightRed: [91, 39]
 });
 
 // Don't use 'blue' not visible on cmd.exe

diff --git a/lib/repl.js b/lib/repl.js
@@ -547,10 +547,38 @@ function REPLServer(prompt,
       });
     } else {
       if (errStack === '') {
-        errStack = `Thrown: ${self.writer(e)}\n`;
-      } else {
-        const ln = errStack.endsWith('\n') ? '' : '\n';
-        errStack = `Thrown:\n${errStack}${ln}`;
+        errStack = self.writer(e);
+      }
+      const lines = errStack.split(/(?<=\n)/);
+      let colors = '';
+      if (options.useColors) {
+        colors = `\u001b[${inspect.colors.brightRed[0]}m` +
+                 `\u001b[${inspect.colors.bold[0]}m`;
+      }
+      let matched = false;
+
+      errStack = colors;
+      for (const line of lines) {
+        if (!matched && /^\[?([A-Z][a-z0-9_]*)*Error/.test(line)) {
+          errStack += writer.options.breakLength >= line.length ?
+            `Uncaught ${line}` :
+            `Uncaught:\n${line}`;
+          matched = true;
+        } else {
+          errStack += line;
+        }
+      }
+      if (!matched) {
+        const ln = lines.length === 1 ? ' ' : ':\n';
+        // eslint-disable-next-line no-control-regex
+        errStack = errStack.replace(/\u001b\[[0-9]{1,3}m/g, '');
+        errStack = `${colors}Uncaught${ln}${errStack}`;
+      }
+      // Normalize line endings.
+      errStack += errStack.endsWith('\n') ? '' : '\n';
+      if (options.useColors) {
+        errStack += `\u001b[${inspect.colors.brightRed[1]}m` +
+                    `\u001b[${inspect.colors.bold[1]}m`;
       }
       top.outputStream.write(errStack);
       top.clearBufferedCommand();

diff --git a/test/parallel/test-repl-harmony.js b/test/parallel/test-repl-harmony.js
@@ -30,7 +30,7 @@ const child = spawn(process.execPath, args);
 const input = '(function(){"use strict"; const y=1;y=2})()\n';
 // This message will vary based on JavaScript engine, so don't check the message
 // contents beyond confirming that the `Error` is a `TypeError`.
-const expectOut = /> Thrown:\nTypeError: /;
+const expectOut = /> Uncaught TypeError: /;
 
 child.stderr.setEncoding('utf8');
 child.stderr.on('data', (d) => {

diff --git a/test/parallel/test-repl-null-thrown.js b/test/parallel/test-repl-null-thrown.js
@@ -20,5 +20,5 @@ replserver.emit('line', '.exit');
 
 setTimeout(() => {
   console.log(text);
-  assert(text.includes('Thrown: null'));
+  assert(text.includes('Uncaught null'));
 }, 0);
diff --git a/test/parallel/test-repl-pretty-custom-stack.js b/test/parallel/test-repl-pretty-custom-stack.js
@@ -48,26 +48,26 @@ const tests = [
   {
     // test .load for a file that throws
     command: `.load ${fixtures.path('repl-pretty-stack.js')}`,
-    expected: 'Thrown:\nError: Whoops!--->\nrepl:*:*--->\nd (repl:*:*)' +
+    expected: 'Uncaught Error: Whoops!--->\nrepl:*:*--->\nd (repl:*:*)' +
               '--->\nc (repl:*:*)--->\nb (repl:*:*)--->\na (repl:*:*)\n'
   },
   {
     command: 'let x y;',
-    expected: 'Thrown:\n' +
-              'let x y;\n      ^\n\nSyntaxError: Unexpected identifier\n'
+    expected: 'let x y;\n      ^\n\n' +
+              'Uncaught SyntaxError: Unexpected identifier\n'
   },
   {
     command: 'throw new Error(\'Whoops!\')',
-    expected: 'Thrown:\nError: Whoops!\n'
+    expected: 'Uncaught Error: Whoops!\n'
   },
   {
     command: 'foo = bar;',
-    expected: 'Thrown:\nReferenceError: bar is not defined\n'
+    expected: 'Uncaught ReferenceError: bar is not defined\n'
   },
   // test anonymous IIFE
   {
     command: '(function() { throw new Error(\'Whoops!\'); })()',
-    expected: 'Thrown:\nError: Whoops!--->\nrepl:*:*\n'
+    expected: 'Uncaught Error: Whoops!--->\nrepl:*:*\n'
   }
 ];
 

diff --git a/test/parallel/test-repl-pretty-stack.js b/test/parallel/test-repl-pretty-stack.js
@@ -7,7 +7,7 @@ const repl = require('repl');
 
 const stackRegExp = /(at .*repl:)[0-9]+:[0-9]+/g;
 
-function run({ command, expected, ...extraREPLOptions }) {
+function run({ command, expected, ...extraREPLOptions }, i) {
   let accum = '';
 
   const inputStream = new ArrayStream();
@@ -25,6 +25,7 @@ function run({ command, expected, ...extraREPLOptions }) {
   });
 
   r.write(`${command}\n`);
+  console.log(i);
   assert.strictEqual(
     accum.replace(stackRegExp, '$1*:*'),
     expected.replace(stackRegExp, '$1*:*')
@@ -36,39 +37,40 @@ const tests = [
   {
     // Test .load for a file that throws.
     command: `.load ${fixtures.path('repl-pretty-stack.js')}`,
-    expected: 'Thrown:\nError: Whoops!\n    at repl:*:*\n' +
+    expected: 'Uncaught Error: Whoops!\n    at repl:*:*\n' +
               '    at d (repl:*:*)\n    at c (repl:*:*)\n' +
               '    at b (repl:*:*)\n    at a (repl:*:*)\n'
   },
   {
     command: 'let x y;',
-    expected: 'Thrown:\n' +
-              'let x y;\n      ^\n\nSyntaxError: Unexpected identifier\n'
+    expected: 'let x y;\n      ^\n\n' +
+              'Uncaught SyntaxError: Unexpected identifier\n'
   },
   {
     command: 'throw new Error(\'Whoops!\')',
-    expected: 'Thrown:\nError: Whoops!\n'
+    expected: 'Uncaught Error: Whoops!\n'
   },
   {
     command: '(() => { const err = Error(\'Whoops!\'); ' +
              'err.foo = \'bar\'; throw err; })()',
-    expected: "Thrown:\nError: Whoops!\n    at repl:*:* {\n  foo: 'bar'\n}\n",
+    expected: "Uncaught Error: Whoops!\n    at repl:*:* {\n  foo: 'bar'\n}\n",
   },
   {
     command: '(() => { const err = Error(\'Whoops!\'); ' +
              'err.foo = \'bar\'; throw err; })()',
-    expected: 'Thrown:\nError: Whoops!\n    at repl:*:* {\n  foo: ' +
-              "\u001b[32m'bar'\u001b[39m\n}\n",
+    expected: '\u001b[91m\u001b[1m' +
+              'Uncaught Error: Whoops!\n    at repl:*:* {\n  foo: ' +
+              "\u001b[32m'bar'\u001b[39m\n}\n\u001b[39m\u001b[22m",
     useColors: true
   },
   {
     command: 'foo = bar;',
-    expected: 'Thrown:\nReferenceError: bar is not defined\n'
+    expected: 'Uncaught ReferenceError: bar is not defined\n'
   },
   // Test anonymous IIFE.
   {
     command: '(function() { throw new Error(\'Whoops!\'); })()',
-    expected: 'Thrown:\nError: Whoops!\n    at repl:*:*\n'
+    expected: 'Uncaught Error: Whoops!\n    at repl:*:*\n'
   }
 ];
 

diff --git a/test/parallel/test-repl-top-level-await.js b/test/parallel/test-repl-top-level-await.js
@@ -118,15 +118,15 @@ async function ordinaryTests() {
     [ 'if (await true) { function bar() {}; }', 'undefined' ],
     [ 'bar', '[Function: bar]' ],
     [ 'if (await true) { class Bar {}; }', 'undefined' ],
-    [ 'Bar', 'ReferenceError: Bar is not defined', { line: 1 } ],
+    [ 'Bar', 'Uncaught ReferenceError: Bar is not defined' ],
     [ 'await 0; function* gen(){}', 'undefined' ],
     [ 'for (var i = 0; i < 10; ++i) { await i; }', 'undefined' ],
     [ 'i', '10' ],
     [ 'for (let j = 0; j < 5; ++j) { await j; }', 'undefined' ],
-    [ 'j', 'ReferenceError: j is not defined', { line: 1 } ],
+    [ 'j', 'Uncaught ReferenceError: j is not defined' ],
     [ 'gen', '[GeneratorFunction: gen]' ],
-    [ 'return 42; await 5;', 'SyntaxError: Illegal return statement',
-      { line: 4 } ],
+    [ 'return 42; await 5;', 'Uncaught SyntaxError: Illegal return statement',
+      { line: 3 } ],
     [ 'let o = await 1, p', 'undefined' ],
     [ 'p', 'undefined' ],
     [ 'let q = 1, s = await 2', 'undefined' ],
@@ -160,7 +160,7 @@ async function ctrlCTest() {
     { ctrl: true, name: 'c' }
   ]), [
     'await timeout(100000)\r',
-    'Thrown:',
+    'Uncaught:',
     '[Error [ERR_SCRIPT_EXECUTION_INTERRUPTED]: ' +
       'Script execution was interrupted by `SIGINT`] {',
     "  code: 'ERR_SCRIPT_EXECUTION_INTERRUPTED'",

diff --git a/test/parallel/test-repl-uncaught-exception-standalone.js b/test/parallel/test-repl-uncaught-exception-standalone.js
@@ -18,8 +18,7 @@ child.on('exit', common.mustCall(() => {
     [
       'Type ".help" for more information.',
       // x\n
-      '> Thrown:',
-      'ReferenceError: x is not defined',
+      '> Uncaught ReferenceError: x is not defined',
       // Added `uncaughtException` listener.
       '> short',
       'undefined',

diff --git a/test/parallel/test-repl-uncaught-exception.js b/test/parallel/test-repl-uncaught-exception.js
@@ -6,7 +6,7 @@ const repl = require('repl');
 
 let count = 0;
 
-function run({ command, expected }) {
+function run({ command, expected, useColors = false }) {
   let accum = '';
 
   const output = new ArrayStream();
@@ -17,7 +17,7 @@ function run({ command, expected }) {
     input: new ArrayStream(),
     output,
     terminal: false,
-    useColors: false
+    useColors
   });
 
   r.write(`${command}\n`);
@@ -30,35 +30,44 @@ function run({ command, expected }) {
   // Verify that the repl is still working as expected.
   accum = '';
   r.write('1 + 1\n');
-  assert.strictEqual(accum, '2\n');
+  // eslint-disable-next-line no-control-regex
+  assert.strictEqual(accum.replace(/\u001b\[[0-9]+m/g, ''), '2\n');
   r.close();
   count++;
 }
 
 const tests = [
   {
+    useColors: true,
     command: 'x',
-    expected: 'Thrown:\n' +
-              'ReferenceError: x is not defined\n'
+    expected: '\u001b[91m\u001b[1m' +
+              'Uncaught ReferenceError: x is not defined\n' +
+              '\u001b[39m\u001b[22m'
+  },
+  {
+    useColors: true,
+    command: 'throw { foo: "test" }',
+    expected: '\u001b[91m\u001b[1m' +
+              "Uncaught { foo: 'test' }\n" +
+              '\u001b[39m\u001b[22m'
   },
   {
     command: 'process.on("uncaughtException", () => console.log("Foobar"));\n',
-    expected: /^Thrown:\nTypeError \[ERR_INVALID_REPL_INPUT]: Listeners for `/
+    expected: /^Uncaught:\nTypeError \[ERR_INVALID_REPL_INPUT]: Listeners for `/
   },
   {
     command: 'x;\n',
-    expected: 'Thrown:\n' +
-              'ReferenceError: x is not defined\n'
+    expected: 'Uncaught ReferenceError: x is not defined\n'
   },
   {
     command: 'process.on("uncaughtException", () => console.log("Foobar"));' +
              'console.log("Baz");\n',
-    expected: /^Thrown:\nTypeError \[ERR_INVALID_REPL_INPUT]: Listeners for `/
+    expected: /^Uncaught:\nTypeError \[ERR_INVALID_REPL_INPUT]: Listeners for `/
   },
   {
     command: 'console.log("Baz");' +
              'process.on("uncaughtException", () => console.log("Foobar"));\n',
-    expected: /^Baz\nThrown:\nTypeError \[ERR_INVALID_REPL_INPUT]:.*uncaughtException/
+    expected: /^Baz\nUncaught:\nTypeError \[ERR_INVALID_REPL_INPUT]:.*uncaughtException/
   }
 ];
 

diff --git a/test/parallel/test-repl-underscore.js b/test/parallel/test-repl-underscore.js
@@ -173,13 +173,11 @@ function testError() {
       'undefined',
 
       // The error, both from the original throw and the `_error` echo.
-      'Thrown:',
-      'Error: foo',
+      'Uncaught Error: foo',
       '[Error: foo]',
 
       // The sync error, with individual property echoes
-      'Thrown:',
-      /^Error: ENOENT: no such file or directory, scandir '.*nonexistent\?'/,
+      /^Uncaught Error: ENOENT: no such file or directory, scandir '.*nonexistent\?'/,
       /Object\.readdirSync/,
       /^  errno: -(2|4058),$/,
       "  syscall: 'scandir',",
@@ -194,8 +192,7 @@ function testError() {
       'undefined',
 
       // The message from the original throw
-      'Thrown:',
-      'Error: baz',
+      'Uncaught Error: baz',
     ];
     for (const line of lines) {
       const expected = expectedLines.shift();
@@ -218,8 +215,7 @@ function testError() {
       "'baz'",
       'Expression assignment to _error now disabled.',
       '0',
-      'Thrown:',
-      'Error: quux',
+      'Uncaught Error: quux',
       '0'
     ]);
   });