sourcecred/config/webpack.config.backend.js
William Chargin 4e8c89abfe
backend: export a normal Webpack config object (#779)
Summary:
Previously, our `webpack.config.backend.js` file actually exported a
function that could be used to make a Webpack configuration object.
(This is not to be confused with the late `makeWebpackConfig.js`, which
actually exported a configuration object!)

In addition to being confusing nomenclature, this was a sneaky trap for
CLI users. Invoking `webpack --config config/webpack.config.backend.js`
would actually work, but do the wrong thing: Webpack _allows_ your
configuration object to be a function, but with different semantics. In
particular, the result was that Webpack would emit the build output into
your current directory instead of into `bin/`.

This commit fixes that by making `webpack.config.backend.js` export the
Webpack configuration object for the backend JavaScript applications.
The logic to change the path is now handled by the caller, by
overwriting `config.output.path`; this is exactly [the same approach
that the Webpack CLI takes when given an `--output-path`][1], so it’s
okay with me.

[1]: 368e2640e6/bin/convert-argv.js (L406-L409)

Test Plan:
Run `yarn backend` and `yarn backend --dry-run`. Note that each runs
with appropriate output (both emitted files and console logs).

wchargin-branch: backend-webpack-config-object
2018-09-05 11:58:20 -07:00

66 lines
2.2 KiB
JavaScript

// @no-flow
const webpack = require("webpack");
const ModuleScopePlugin = require("react-dev-utils/ModuleScopePlugin");
const RemoveBuildDirectoryPlugin = require("./RemoveBuildDirectoryPlugin");
const paths = require("./paths");
const nodeExternals = require("webpack-node-externals");
const getClientEnvironment = require("./env");
const env = getClientEnvironment();
// This is the backend configuration. It builds applications that target
// Node and will not run in a browser.
module.exports = {
// Don't attempt to continue if there are any errors.
bail: true,
// Target Node instead of the browser.
target: "node",
entry: paths.backendEntryPoints,
externals: [nodeExternals()],
output: {
path: paths.backendBuild,
// Generated JS file names (with nested folders).
// There will be one main bundle, and one file per asynchronous chunk.
// We don't currently advertise code splitting but Webpack supports it.
filename: "[name].js",
chunkFilename: "[name].[chunkhash:8].chunk.js",
libraryTarget: "umd",
},
resolve: {
extensions: [".js", ".json"],
plugins: [
// Prevents users from importing files from outside of src/ (or node_modules/).
// This often causes confusion because we only process files within src/ with babel.
// To fix this, we prevent you from importing files out of src/ -- if you'd like to,
// please link the files into your node_modules/ and let module-resolution kick in.
// Make sure your source files are compiled, as they will not be processed in any way.
new ModuleScopePlugin(paths.appSrc, [paths.appPackageJson]),
],
},
module: {
strictExportPresence: true,
rules: [
{
// "oneOf" will traverse all following loaders until one will
// match the requirements. If no loader matches, it will fail.
oneOf: [
// Process JS with Babel.
{
test: /\.(js|jsx|mjs)$/,
include: paths.appSrc,
loader: require.resolve("babel-loader"),
options: {
compact: true,
},
},
],
},
],
},
plugins: [
new RemoveBuildDirectoryPlugin(),
new webpack.DefinePlugin(env.individuallyStringified),
],
};