Question

When utilizing node.js’s newish support for --eval, I get an error (ReferenceError: require is not defined) when I attempt to use require().

Here’s an example of the failure:

$ node --eval 'require("http");'

undefined:1

^
ReferenceError: require is not defined
    at eval at <anonymous> (node.js:762:36)
    at eval (native)
    at node.js:762:36
$

Here’s a working example of using require() typed into the REPL:

$ node
> require("http");
{ STATUS_CODES: 
   { '100': 'Continue'
   , '101': 'Switching Protocols'
   , '102': 'Processing'
   , '200': 'OK'
   , '201': 'Created'
   , '202': 'Accepted'
   , '203': 'Non-Authoritative Information'
   , '204': 'No Content'
   , '205': 'Reset Content'
   , '206': 'Partial Content'
   , '207': 'Multi-Status'
   , '300': 'Multiple Choices'
   , '301': 'Moved Permanently'
   , '302': 'Moved Temporarily'
   , '303': 'See Other'
   , '304': 'Not Modified'
   , '305': 'Use Proxy'
   , '307': 'Temporary Redirect'
   , '400': 'Bad Request'
   , '401': 'Unauthorized'
   , '402': 'Payment Required'
   , '403': 'Forbidden'
   , '404': 'Not Found'
   , '405': 'Method Not Allowed'
   , '406': 'Not Acceptable'
   , '407': 'Proxy Authentication Required'
   , '408': 'Request Time-out'
   , '409': 'Conflict'
   , '410': 'Gone'
   , '411': 'Length Required'
   , '412': 'Precondition Failed'
   , '413': 'Request Entity Too Large'
   , '414': 'Request-URI Too Large'
   , '415': 'Unsupported Media Type'
   , '416': 'Requested Range Not Satisfiable'
   , '417': 'Expectation Failed'
   , '418': 'I\'m a teapot'
   , '422': 'Unprocessable Entity'
   , '423': 'Locked'
   , '424': 'Failed Dependency'
   , '425': 'Unordered Collection'
   , '426': 'Upgrade Required'
   , '500': 'Internal Server Error'
   , '501': 'Not Implemented'
   , '502': 'Bad Gateway'
   , '503': 'Service Unavailable'
   , '504': 'Gateway Time-out'
   , '505': 'HTTP Version not supported'
   , '506': 'Variant Also Negotiates'
   , '507': 'Insufficient Storage'
   , '509': 'Bandwidth Limit Exceeded'
   , '510': 'Not Extended'
   }
, IncomingMessage: { [Function: IncomingMessage] super_: [Function: EventEmitter] }
, OutgoingMessage: { [Function: OutgoingMessage] super_: [Function: EventEmitter] }
, ServerResponse: { [Function: ServerResponse] super_: [Circular] }
, ClientRequest: { [Function: ClientRequest] super_: [Circular] }
, Server: 
   { [Function: Server]
     super_: { [Function: Server] super_: [Function: EventEmitter] } }
, createServer: [Function]
, Client: 
   { [Function: Client]
     super_: { [Function: Stream] super_: [Function: EventEmitter] } }
, createClient: [Function]
, cat: [Function]
}
> 

Is there a way to use require() with node’s --eval?

I’m on node 0.2.6 on Mac OS X 10.6.5.

Answer 1

No, at least not in 2.x.

By looking at the source of 2.6:

} else if (process._eval) {
  // -e, --eval
  var indirectEval= eval; // so the eval happens in global scope.
  if (process._eval) console.log(indirectEval(process._eval));

It becomes clear that Node.js does not setup any of wrapper code for the eval’d code, therefore require etc. are not available.

But this was changed in the 3.x version:

} else if (process._eval) {
  // -e, --eval
  var rv = new module.Module()._compile('return eval(process._eval)', 'eval');
  console.log(rv);

So in 3.x eval’d code works just like a regular module.