Syntax Validator checks for mistakes and errors

return 42; // Return statement not inside a function

function f() {
  'use strict';

  // No more octal
  var x = 042;

  // Duplicate property
  var y = { x: 1, x: 2 };

  // With statement can't be used
  with (z) {}

No result yet.

Unlike a typical code linter, this syntax validator does not care about coding styles and formatting.

If there is a syntax error, the sign will be shown in the left-side gutter. Placing the mouse cursor over that sign will reveal the complete error description.

For a command-line usage, check esvalidate from Esprima package (for Node.js). There is also a plugin for Grunt called grunt-jsvalidate. Ant users can take a look at an exemplary Ant task for syntax validation.