Hot Module Replacement
Elmish applications can benefit from Hot Module Replacement (known as HMR).
This allow us to modify the application while it's running, without a full reload. Your application will now maintain its state between two changes.
Installation
Add Fable package with paket: Add Example: Parcel and Vite, are supported since version 4.2.0. They don't require any specific configuration. The package will include the HMR support only if you are building your program with You need to always include For example, if you use You can also usepaket add nuget Fable.Elmish.HMRWebpack configuration
hot: true andinline: true (only for webpack < v5.0.0) to yourdevServer node.// ...devServer: {// ... hot:true}// ...Parcel and Vite
Usage
DEBUG set in your compilation conditions. Fable adds it by default when in watch mode.open Elmish.HMR after your othersopen Elmish.XXX statements. This is needed to shadow the supported APIs.Elmish.Program.run it will be shadowed asElmish.HMR.Program.run.openElmishopenElmish.ReactopenElmish.HMR// See how this is the last open statementProgram.mkProgram init update view|> Program.withReactSynchronous"elmish-app"|> Program.runElmish.Program.runWith if you need to pass custom arguments,runWith will also be shadowed asElmish.HMR.Program.runWith:Program.mkProgram init update view|> Program.withReactSynchronous"elmish-app"|> Program.runWith("custom argument",42)