Also keep in mind that javascript engines have a built-in mechanism for including multi-line strings with a powerful substitution engine: tagged template strings (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...). The upside of template strings is that you can run your code directly in node or electron without using extra tooling first. It is possible and not hard to use tagged templates with react, although few people do. It's more common in some other frontend ecosystems.