Creating a template engine for Express

- [Narrator] In this video, I will show you…to use the API function app.engine,…to create the template engine.…I'm still using my hello world sample for that.…You don't necessarily have…to code along with me.…Just watch what I'm doing.…Express comes with a variety…of supported template engines.…But let's assume for a moment…that we want to create our own.…Let's say, one that renders mark down to HTML,…how would we implement that?…As Express is built for extensibility,…adding this is actually quite easy.…

So I'm here in my index js file…and now I'll write on top…after application was instantiated,…I will add app.engine…and this takes as first argument…the name of the engine…and it should be md for marked down…and then I create an async function…the signature for app.engine tells us…that this function gets a file path…an options object…and a callback function.…

So we now obviously have to open this file.…For that, I bring in, const fs equals require fs.…Because we need read file from it…and I also want…to create a promisify version…