lib: repl add .load-editor feature

doc/api/repl.md

@@ -39,6 +39,8 @@ The following special commands are supported by all REPL instances:
 * `.load` - Load a file into the current REPL session.
   `> .load ./file/to/load.js`
 * `.editor` - Enter editor mode (`<ctrl>-D` to finish, `<ctrl>-C` to cancel)
+* `.load-editor` - Load a file and enter editor mode (`<ctrl>-D` to finish, `<ctrl>-C` to cancel)
+  `> .load-editor ./file/to/load.js`
 
 <!-- eslint-skip -->
 ```js

lib/repl.js

@@ -1284,6 +1284,35 @@ function defineDefaultCommands(repl) {
         '// Entering editor mode (^D to finish, ^C to cancel)\n');
     }
   });
+
+  repl.defineCommand('load-editor', {
+    help: 'Load a file and enter editor mode',
+    action: function(file) {
+      if (!this.terminal) return;
+      this.editorMode = true;
+      REPLServer.super_.prototype.setPrompt.call(this, '');
+      this.outputStream.write(
+        '// Entering editor mode (^D to finish, ^C to cancel)\n');
+      try {
+        var stats = fs.statSync(file);
+        if (stats && stats.isFile()) {
+          var data = fs.readFileSync(file, 'utf8');
+          var lines = data.split('\n');
+          this.displayPrompt();
+          for (var n = 0; n < lines.length; n++) {
+            if (lines[n])
+              this.write(`${lines[n]}\n`);
+          }
+        } else {
+          this.outputStream.write('Failed to load:' + file +
+            ' is not a valid file\n');
+        }
+      } catch (e) {
+        this.outputStream.write('Failed to load:' + file + '\n');
+      }
+      this.displayPrompt();
+    }
+  });
 }
 
 function regexpEscape(s) {

test/parallel/test-repl-definecommand.js

@@ -35,7 +35,7 @@ r.defineCommand('say2', function() {
 });
 
 inputStream.write('.help\n');
-assert(/\n\.say1     help for say1\n/.test(output),
+assert(/\n\.say1          help for say1\n/.test(output),
        'help for say1 not present');
 assert(/\n\.say2\n/.test(output), 'help for say2 not present');
 inputStream.write('.say1 node developer\n');

test/parallel/test-repl-load-editor.js

@@ -0,0 +1,112 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+const repl = require('repl');
+
+// \u001b[1G - Moves the cursor to 1st column
+// \u001b[0J - Clear screen
+// \u001b[3G - Moves the cursor to 3rd column
+const terminalCode = '\u001b[1G\u001b[0J> \u001b[3G';
+const terminalCodeRegex = new RegExp(terminalCode.replace(/\[/g, '\\['), 'g');
+
+function run({ input, filename, errormsg, output, event,
+               checkTerminalCodes = true }) {
+  const stream = new common.ArrayStream();
+  let found = '';
+
+  stream.write = (msg) => found += msg.replace('\r', '');
+
+  let expected = `${terminalCode}.load-editor ${filename}\n` +
+                 '// Entering editor mode (^D to finish, ^C to cancel)\n' +
+                 `${errormsg}${input}${output}\n${terminalCode}`;
+
+  const replServer = repl.start({
+    prompt: '> ',
+    terminal: true,
+    input: stream,
+    output: stream,
+    useColors: false
+  });
+
+  stream.emit('data', `.load-editor ${filename}\n`);
+  stream.emit('data', input);
+  replServer.write('', event);
+  replServer.close();
+
+  if (!checkTerminalCodes) {
+    found = found.replace(terminalCodeRegex, '').replace(/\n/g, '');
+    expected = expected.replace(terminalCodeRegex, '').replace(/\n/g, '');
+  }
+
+  assert.strictEqual(found, expected);
+}
+
+const tests = [
+  {
+    input: '',
+    filename: 'notexistfile.js',
+    errormsg: `Failed to load:notexistfile.js\n${terminalCode}\n`,
+    output: '(To exit, press ^C again or type .exit)',
+    event: { ctrl: true, name: 'c' }
+  },
+  {
+    input: 'var i = 1;\ni + 3',
+    filename: 'notexistfile.js',
+    errormsg: `Failed to load:notexistfile.js\n${terminalCode}`,
+    output: '\n4',
+    event: { ctrl: true, name: 'd' }
+  }
+];
+
+tests.forEach(run);
+
+// Auto code alignment for .editor mode
+function testCodeAligment({ input, cursor = 0, line = '' }) {
+  const stream = new common.ArrayStream();
+  const outputStream = new common.ArrayStream();
+
+  stream.write = common.mustNotCall('writing not allowed');
+
+  const replServer = repl.start({
+    prompt: '> ',
+    terminal: true,
+    input: stream,
+    output: outputStream,
+    useColors: false
+  });
+
+  stream.emit('data', '.load-editor\n');
+  input.split('').forEach((ch) => stream.emit('data', ch));
+  // Test the content of current line and the cursor position
+  assert.strictEqual(line, replServer.line);
+  assert.strictEqual(cursor, replServer.cursor);
+
+  replServer.write('', { ctrl: true, name: 'd' });
+  replServer.close();
+  // Ensure that empty lines are not saved in history
+  assert.notStrictEqual(replServer.history[0].trim(), '');
+}
+
+const codeAlignmentTests = [
+  {
+    input: 'var i = 1;\n'
+  },
+  {
+    input: '  var i = 1;\n',
+    cursor: 2,
+    line: '  '
+  },
+  {
+    input: '     var i = 1;\n',
+    cursor: 5,
+    line: '     '
+  },
+  {
+    input: ' var i = 1;\n var j = 2\n',
+    cursor: 2,
+    line: '  '
+  }
+];
+
+codeAlignmentTests.forEach(testCodeAligment);