This example shows Hot Module Replacement (HMR) for the three platform setups, all sharing one module that gets hot-swapped at runtime.

The download/apply runtime is the same everywhere; only the trigger (what tells the app to check for an update) differs:

• Web — webpack/hot/dev-server reacts to the update signal pushed by webpack-dev-server over EventSource. Run it with webpack serve.
• Node — there is no EventSource, so a Node trigger drives the check: webpack/hot/poll re-checks on a timer (webpack/hot/signal waits for a process signal). Run it with webpack --watch and node dist/node/main.js, then edit message.js.
• Universal — one ESM bundle for web and Node. webpack/hot/dev-server is universal: it consumes the same update signal on either platform (a browser dev-server, or a Node dev-server/middleware feeding the emitter), so no per-target client is needed.

Edit message.js while the app runs to see the module reload in place — no full restart, no page reload.

message.js

_{{message.js}}_

web.js

_{{web.js}}_

node.js

_{{node.js}}_

universal.js

_{{universal.js}}_

webpack.config.js

_{{webpack.config.js}}_