Systemjs: `cannot find module "vm"` when using SystemJS > 0.21.0 with webpack

[rdeits]

When using webpack to package systemjs versions > 0.21.0, I get the following warning during webpack bundling:

    WARNING in ./node_modules/systemjs/dist/system.js
    4:36270-36272 Critical dependency: require function is used in a way in which dependencies cannot be statically extracted
     @ ./node_modules/systemjs/dist/system.js
     @ ./index.js

attempting to call SystemJS.import() in the packaged module results in:

Error: Cannot find module "vm".
  Instantiating http://cdnjs.cloudflare.com/ajax/libs/p5.js/0.5.11/p5.js
  Loading http://cdnjs.cloudflare.com/ajax/libs/p5.js/0.5.11/p5.js

I can reproduce the issue with systemjs 0.21.1, 0.21.2, and 0.21.3. Version 0.21.0 seems to work just fine.

I've put together a minimal reproduction of the issue in this repo: https://github.com/rdeits/systemjs-issue-repro . You can try editing the systemjs version in package.json to verify that the issue goes away with 0.21.0.

Is there anything else I can do to help debug this?

[guybedford]

Perhaps try using the SystemJS production loader instead here and see if that works better?

[rdeits]

Thanks! The production loader works fine with 0.21.3, although I'm not sure we want to give up all the module support that the dev loader offers.

[rdeits]

By the way, this is the line where webpack loses track of the required dependencies: https://github.com/systemjs/systemjs/blob/6fdd0a95dc5a6a33920e571a1d1890430853da70/src/systemjs-loader.js#L79

[travigd]

For posterity's sake, I ran into this issue as well and was able to fix it by monkey patching SystemJS's _nodeRequire to be undefined.

if (SystemJS._nodeRequire) {
  // Fixes https://github.com/systemjs/systemjs/issues/1817
  // SystemJS basically will try to detect if it should use NodeJS's built-in
  // require to load things if it can, but because Webpack (sometimes, depending
  // on the settings/target I think?) defines `require`, SystemJS can get
  // confused. When it gets confused, it tries to use Webpack's require (which
  // then complains since the things we're trying to load dynamically weren't
  // loaded by Webpack). This is our hack to un-confuse SystemJS.
  console.warn("Monkey-patchings SystemJS._nodeRequire to undefined.");
  SystemJS._nodeRequire = undefined;
}