Does not support require.ensure error callback added in Webpack 2.4

[jharris4]

Webpack 2.4 added support for error callbacks as a 2nd argument to require.ensure:

webpack/webpack#4069

This is not supported by the bundle-loader, but there is a forked version of the loader that does support the require.ensure error callback: https://github.com/jharris4/split-chunk-loader

I'd consider making a PR to merge the changes from split-chunk-loader into bundle-loader, but not sure of the best way to handle the fact that webpack >= 2.4 is required for that to work. Maybe adding a peerDependency would do the trick?

[michael-ciniawsky]

If you have the time and have something in mind already please feel free to send PR, it would be apprectiated 😛
In regrads to necessity of webpack >= v2.4.0, a peerDependency would be fine imho, but I need to discuss && verify that. In any case we will find a solution to deal with it, so your PR won't be wasted :)

[jharris4]

PR created: #48