gnode

Run node with ES6 Generators, today!

gnode is a very light wrapper around your node executable that ensures ES6 Generator support, even on versions of node that do not support ES6 Generators natively.

You use it exactly like the regular node executable, except that you do not need to pass the --harmony-generators flag. That is where the magic happens.

With gnode you can use co or suspend, or any other Generator-based flow control based module, today!

How does this magic work?

node < 0.11.3

When V8 provides no native ES6 generators support, then gnode invokes a node instance with a patched require.extensions['.js'] function, which transparently transpiles your ES6 code with Generators into ES5-compatible code. We can thank facebook/regenerator for making this possible.

Under the hood, this command:

$ gnode foo.js all the args

Turns into something like this:

$ GNODE_ENTRY_POINT=foo.js node fallback.js all the args

node >= 0.11.3

When V8 supports ES6 generators natively, then gnode invokes a node instance with the --harmony-generators flag passed in transparently, so that the native generators are used, and no transpiling takes place. Everything else just works as you would expect it to.

Under the hood, this command:

$ gnode foo.js all the args

Turns into something like this:

$ node --harmony-generators foo.js all the args

Installation

Install the gnode executable via npm:

$ npm install -g gnode

CLI Examples

The gnode executable uses whatever version of node is installed in your PATH:

Here's our example t.js file:

var co = require('co');

function sleep (ms) {
  return function (fn) {
    setTimeout(fn, ms);
  };
}

co(function* () {
  for (var i = 0; i < 5; i++) {
    console.log(i);
    yield sleep(1000);
  }
})();

This script with an ES6 Generator in it can be run using any version of node by using gnode:

☮ ~ (master) ∴ n 0.8.26

☮ ~ (master) ∴ gnode -v
v0.8.26

☮ ~ (master) ∴ gnode t.js
0
1
2
3
4

☮ ~ (master) ∴ n 0.10.21

☮ ~ (master) ∴ gnode -v
v0.10.21

☮ ~ (master) ∴ gnode t.js
0
1
2
3
4

☮ ~ (master) ∴ n 0.11.8

☮ ~ (master) ∴ gnode -v
v0.11.8

☮ ~ (master) ∴ gnode t.js
0
1
2
3
4

Programmatic API

You can also just require('gnode') in a script without any generators, and then require() any other .js file that has generators after that.

require('gnode');
var gen = require('./someGenerator');
// etc…