process.env.NODE_ENV variables into scss via webpack - sass

Question

Is there a way to reference a process.env.NODE_ENV in a scss file by passing it to the sass-loader in web-pack. If so anyone know how to go about this ?
Here is my webpack module lodaers array.
module: {
loaders: [
{ test: /\.js?$/,
loader: 'babel-loader',
include: path.join(__dirname, '../app'),
exclude: /node_modules/
},
{ test: /\.scss?$/,
loader: 'style-loader!css-loader!sass-loader',
include: path.join(__dirname, '../app', 'styles')
},
{
test: /\.(jpe?g|png|gif|svg)$/i,
include : path.join(__dirname, '../app', 'images'),
loader : 'file-loader?limit=30000&name=[name].[ext]'
},
{
test: /\.(ttf|eot|svg|woff(2)?)(\?[a-z0-9]+)?$/,
include : path.join(__dirname, '../app', 'fonts'),
loader: 'file-loader?name=fonts/[name].[ext]'
}
]
I even tried
{ test: /\.scss?$/,
loader: 'style-loader!css-loader!sass-loader',
include: path.join(__dirname, '../app', 'styles'),
options: {
data: "$env: " + process.env.NODE_ENV + ";"
}
}
but the above broke the build.
I just want a way to access a url in my scss file depending on the environment.
It doesn't have to be via webpack any ideas would help without hard coding it.
for example:
.contact-transparent{
width: 100%;
height: 100%;
background: url(process.env.NODE_ENV+'/home-background.jpg') left center no-repeat;
}

Answer 1

I think you could get this done with a custom loader that you chain in before the others for your Sass files. In that loader you would check the value of NODE_ENV and do a find/replace in the Sass source, where the replaced value is based on the env. Not fancy but would get the job done. For example:
// url-by-env-loader.js
module.exports = (source) => {
const urlsByEnv = {
dev: "the-dev-host.com",
staging: "the-staging-host.com",
prod: "the-prod-host.com"
};
const urlToReplace = "the-url-in-your-sass-source.com";
const urlToUse = urlsByEnv[process.env.NODE_ENV];
const replaceRegex = new RegExp(urlToReplace, 'g');
return source.replace(replaceRegex, urlToUse);
}