TypeScript
You can add Pd4Webs TypeScript definitions for its JavaScript API to your project to benefit from type-checking, auto-completion, and inline documentation. The TypeScript definitions are found here.
Exactly how to add these types to your project so that your IDE/editor uses them depends on your project's technology stack; generally, you should be able to copy the file to your project's root directory — or ./src — and your IDE/editor will pick up the definitions.