Webpack 2 and Hot module replacement

[thangngoc89]

We're migrating to webpack 2 at Phenomic but HMR isn't working for us. Did you test with webpack 2 and HMR ?

Our branch is here https://github.com/MoOx/phenomic/tree/webpack-2

Our dev-server is an express instance with webpack-dev-middleware and webpack-hot-middleware

Behaviours:

• Route /**.hot-update.json not found
• Client doesn't fetch the new hot-update hash correctly.
  • If I start the dev server, make a change to trigger HMR. Via /__webpack_hmr I can see that the new hash for hot-update is A. Client fetches /A.hot-update.json but it's a route not found as I said above.
  • Next, I make another update and get hash B. Client still fetches A.hot-update.json
  • Restart dev server, make a changes, now the client fetches hash B.

[mzgoddard]

@thangngoc89 I have tested with webpack 2. I'm not sure if I've tested with webpack 2's hmr. I'll take a look.

[MoOx]

Thank you!

[mzgoddard]

@thangngoc89 @MoOx I'll have a change up soon that'll fix this.

The problem is HardSource currently runs a pre-compile to detect module's harmony imports and exports changing (cause it means it needs to invalidate the dependency and rebuild it). That pre-compile is interfering with HMR leading it to think no change happened in the build. Cool thing from this I found that webpack 2 adds a new entry point (need-additional-pass) to make webpack optionally perform multiple passes. Rewriting the pre-compile into performing an additional pass instead will fix HMR and make HardSource less hacky!

[thangngoc89]

@mzgoddard Thank you. You're awesome