fable-loader

fable-loader

Webpack loader for Fable (F# to JS compiler)

Installation

npm install fable-loader fable-compiler @babel/core

Usage

Create a webpack-config.js like the following and run it using Webpack (e.g. npx webpack).

ATTENTION: In Fable 2.0 you had to call Webpack through the dotnet-fable CLI tool, starting from Fable 2.1 you call Webpack directly. For example, if you used the command dotnet fable webpack -- --config src/webpack.config.js, replace it with npx webpack --config src/webpack.config.js (you can also use yarn instead of npx). Note you don't need the -- separator anymore.

NOTE: The actual F# to JS compilation is done by fable-compiler. You can control the compiler version through this package.

See the Fable webpack-config-template for a more comprehensive example of a Webpack configuration for Fable projects.

var path = require("path");

module.exports = {
    mode: "production",
    entry: "./src/App.fsproj",
    output: {
        path: path.join(__dirname, "./public"),
        filename: "bundle.js",
    },
    devServer: {
        contentBase: "./public",
        port: 8080,
    },
    module: {
        rules: [{
            test: /\.fs(x|proj)?$/,
            use: "fable-loader"
        }]
    }
}

Options

These are the options that can be passed to fable-loader:

• babel: Babel options (only applied when transforming F# files, you may want to use the babel-loader if you also have JS files in your project).
• define: Array of compilation constants passed to the F# compiler. Fable automatically defines FABLE_COMPILER and fable-loader will also define DEBUG in Webpack "development" mode.
• typedArrays: Translate numeric arrays as JS Typed Arrays. True by default.
• clampByteArrays: If true, Fable will translate byte arrays as Uint8ClampedArray.
• silent: If true, Fable won't output any log (requires fable-compiler >=2.3.14).