Can't require velocity within node.js due to document.createElement calls

[KyleAMathews]

I'm building an isomorphic site using React.js and Velocity for some animations. I'm running into a problem however when rendering pages on the server, pages that require Velocity throw errors on the server due to document not being defined.

[ydaniv]

why should you require Velocity on the server?

[KyleAMathews]

In order to render my React pages on the server.

[ydaniv]

Velocity is used for animation, so I'm confused here. How do you use it for rendering?

[KyleAMathews]

It isn't used for rendering on the server but as I'm using commonjs modules, it still has to be required server-side so that Webpack can bundle it together for sending to the client.

[ydaniv]

@KyleAMathews have you tried simply patching this module and replace all requires with a mock?

[Polyrhythm]

The solution I've had to use repeatedly in other open-source projects used isomorphically is adding an early return in a conditional that checks for window or document or some such. Honestly, this is going to get worse and worse as more people attempt isomorphic apps, so it's probably a good thing to keep in mind.

It would be great if I didn't have to make my own fork of this that is node-compatible. I can't conditionally import modules in my codebase so everything the client uses, the server must also at least be able to require.

[dantman]

@KyleAMathews

It isn't used for rendering on the server but as I'm using commonjs modules, it still has to be required server-side so that Webpack can bundle it together for sending to the client.

I'm using React in a similar way (but with browserify). But I just move call require calls for client-only stuff into the actual client-only methods that use them.

Alternatively require('is-browser') would work.

There's a plethora of client-only js libraries that probably will never fix themselves to mock load server-side. And the idea of loading a client-only module server-side that you don't actually use sounds terrible from what I think should be a best practice. So honestly I think the solution is going to have to be something generic, probably related to the loaders. Instead of going around telling libraries they should make their library a no-op when window/document aren't available.

[KyleAMathews]

Webpack doesn't support conditional requires like browserify does afaik.

Agree that a general workaround would be nice.

[ydaniv]

@KyleAMathews (asking again) have you tried patching the require() of Velocity, e.g. by using proxyquire?

[andrewburgess]

Just to toss in an additional usage case and show how it might be integrated in a React application: https://gist.github.com/tkafka/0d94c6ec94297bb67091

Something like that should be able to be rendered on the server (the functions componentWillEnter and componentWillLeave that trigger the animation are only called from the client side).

[sogko]

@KyleAMathews

I have a similar use-case (using velocity-animate in an isomorphic app). You can use conditional require in webpack, ~~but you have to create two separate webpack bundles:~~, you just need to mock the library

Here's what I've done:

The javascript

var Velocity;
if (typeof window !== 'undefined') {
  Velocity = require('velocity-animate');
} else {
  // mocked velocity library
  Velocity = function() {
    return Promise().resolve(true);
  };
}

// code that uses the library below
...

[psoares]

#578 I created seems to be related to this issue too. Can't do dojo builds without code modifications, because dojo builds are created on the server through nodejs or rhino.

[Rycochet]

From a quick look:

Most of the createElement calls are relating to IE8 support. There is one used to help determine browser prefixes. If the prefix detection gets pulled into a separate module and does feature detection then that should clean up things nicely.

[alampros]

For those interested, I was able to get this working by using the (modified) shim (similar to the above solution) from velocity-react and using patched versions of velocity.js and velocity-ui.js.

[pizzarob]

Something I did that worked well was use webpack's code splitting inside of React's componentDidMount lifecycle method. componentDidMount does not execute server side.

  componentDidMount() {
    import('velocity-animate').then(Velocity => {
      this.velocityScroll = () => {
        Velocity(this.selection, 'scroll', {
          duration: 1000,
          easing: 'easeOutExpo',
        });
      };
    });
  }

https://webpack.js.org/guides/code-splitting-async/