Rails4G (19) [Avatar] Offline
Listings should display the filename in the heading so it's easy to find. I find myself having to read the prior paragraph to see which file it relates to. Common practice to have it in the heading.

e.g. Listing 3.1 Transcode Video Lambda

That refers to index.js.

Also, please block out any commands we should be entering, separating them outside of a paragraph.

e.g., after setting up Listing B.1 Transcode video package.json you should run npm install.

After the listing have a block

> npm install

It helps to separate reading for learning vs. doing. Having them combined leads to mistakes.