Environment variables in manifest.json - Chrome Extension - reactjs

Question

Is it possible to set environment variables in the manifest.json file of a Chrome Extension?

Answer 1

Like wOxxOm said, I used webpack to proccess manifest.json.
In my case, I needed to set version automatically on manifest file.
I added to webpack script:
plugins: [
new CopyWebpackPlugin([
{
from: "public/manifest.json",
to: "manifest.json",
transform(content, path) {
return modify(content)
}
}
]),
]
And the modify function replaces version on file for the parameter:
function modify(buffer) {
var manifest = JSON.parse(buffer.toString());
let argv = process.argv[2];
if (argv) manifest.version = argv.split("=")[1];
let manifest_JSON = JSON.stringify(manifest, null, 2);
return manifest_JSON;
}
So, I build like "yarn build --version=x.x" and webpack do what I need.
PS: if you're going to use this, remember to change:
the manifest.json directory, if necessary;
the value in the modify function, in my case it was version

Answer 2

As the OP has mentioned in her answer, using the copy-webpack-plugin in the webpack.config.js file is the way to go if you're building your Chrome Extension with React. However, if your React app is based on create-react-app, directly editing the webpack.config.js file (which is located in node_modules/react-scripts/config) is not recommended.
In such a case, use craco, which is an npm package that can be used to customize an app based on create-react-app. Here's how you do it:
Install craco into your project using npm i #craco/craco.
Install copy-webpack-plugin as a dev-dependency in your project using npm i --save-dev copy-webpack-plugin.
Let's suppose we're creating a development and a production build of our Chrome Extension. Let's also suppose we've already assigned "version": "0.1.0" in our Chrome Extension's manifest.json. Depending on the build type, we'd like to assign accordingly the version_name field in our Chrome Extension's manifest.json, e.g., "version_name": "0.1.0 dev" for development and "version_name": "0.1.0" for production. In your React app's package.json, introduce two fields (the script names can be whatever you wish) as follows:
"scripts": {
...
"build-dev": "CRX_ENV=dev craco build", // or "set CRX_ENV=dev&& craco build" in the case of Windows
"build-prod": "CRX_ENV=prod craco build", // or "set CRX_ENV=prod&& craco build" in the case of Windows
...
}
Create a new file called craco.config.js in the root of your project. As per your need, do something similar to the following in the craco.config.js file:
const CopyPlugin = require("copy-webpack-plugin")
module.exports = {
webpack: {
plugins: [
new CopyPlugin({
patterns: [
{
from: "public/manifest.json",
to: "manifest.json",
transform(content, path) {
return modifyManifest(content)
},
},
],
}),
],
},
}
function modifyManifest(buffer) {
const manifest = JSON.parse(buffer.toString())
if (process.env.CRX_ENV === "dev") {
manifest.version_name = `${manifest.version} dev`
} else if (process.env.CRX_ENV === "prod") {
manifest.version_name = `${manifest.version}`
}
const manifestJson = JSON.stringify(manifest, null, 2)
return manifestJson
}
Run npm run build-dev. It will create a folder called build in your project root. This build folder is your unpacked Chrome Extension, which you can load into Chrome using the "Load unpacked" button on the chrome://extensions page. Once loaded, you should be able to see 0.1.0 dev as the version name of your Chrome Extension.
Delete the build folder created from the previous step and run npm run build-prod, and repeat the same steps. You should be able to see 0.1.0 as the version name of your Chrome Extension on the chrome://extensions page.