That’s great @Kasra - thank you. Would you be really kind and point me to a link on the syntax to use to install packages from npm. I was no doubt looking in the wrong place but couldn’t find it today.
Once you’ve created your custom block and installed the blocks command line tool, you’ll have your block’s code on your computer. From there, you can run
npm install --save d3 to install d3.
Here’s a good place to start: Airtable Blocks SDK
Note that you’ll need to sign up for the beta to create custom blocks: Custom apps developer survey