@babel/how-to

More and more developers are using Babel in their build process, but do you know how it internally works?

We will first briefly discuss the different parts that compose a JavaScript to JavaScript compiler, and how it tries to reduce the complexity of implementing a custom code transformer: it's not just a search & replace based on regular expressions!

Then, we will learn how Babel implements support for new ECMAScript proposals, by going through a plugin which will transform future syntax to old ECMAScript. In order to code it correctly, we will need to understand the proposed semantics, and we will discuss the trade-offs between specification compliancy and output complexity.