Support AMD/RequireJS.

[mbostock]

When d3.js is loaded, it now prefers the AMD define function or module.exports if available; the global d3 is only set if neither of these are available. A side benefit of this change is that browserify, bower and component can now load the D3 library directly rather than needing a custom definition.

[sheppard]

Cool, thanks!

I was just about to throw out another option based on this example.

Pros: works with the return from the old closure, and puts all the moduley stuff at the top of the built file.
Cons: a bit more convoluted

(function (root, factory) {
    if (typeof define === 'function' && define.amd) {
        // AMD. Register as an anonymous module.
        define(factory);
    /* EDIT: instead of this: 
    } else if (typeof exports === 'object') {
    do this: */
    } else if (typeof module === "object" && module.exports) {
        // Node. Does not work with strict CommonJS, but
        // only CommonJS-like enviroments that support module.exports,
        // like Node.
        module.exports = factory();
    } else {
        // Browser globals (root is window)
        root.d3 = factory();
  }
}(this, function () {
    var d3 = {};
    // make d3
    return d3;
}));

I'm fine leaving it as you have it now.

[mbostock]

The only effective difference is using typeof exports === 'object' rather than our current longer typeof module === "object" && module.exports, right? I feel like the latter is more robust, but then again this whole thing seems like a cludge anyway. :)

[sheppard]

Yes, I just noticed that after copying the example. I agree that typeof module === "object" && module.exports is a better test - I meant for the example to be effectively the same. My main point was just to show the difference in where the cludge actually appears in the file.

[sheppard]

It'd be less cludgy if everyone would just use AMD :)

Ok I'll stop

[mbostock]

Obligatory XKCD reference: 😁

[mbostock]

Folded into #1690.