We've written our code so now we need to build it.

We are writing a crate that should be used in the browser, so we run this in our terminal:

$ wasm-pack build

If you were writing a package that should be used in Node.js (with CommonJS modules, e.g. require), you would run this in your terminal:

$ wasm-pack build --target nodejs

This command when run does a few things:

1. It'll compile your code to wasm if you haven't already
2. It'll generate a pkg folder with the wasm file, a JS wrapper file around the wasm, your README, and a package.json file.