⚠️ Ensure you've read What are headless components? before attempting to build any components yourself.
Consider what commerce concepts and/or data objects you’ll be working with for the component, how they are represented in the Shopify Storefront API, which data is essential for them, and which resources use them.
For example, if you want to build a component to handle prices and money, it’s important to know the amount and the currency code. It’s also important to know that there are prices associated with ProductVariants, and price ranges for Products. This helps you determine which essential data or props are needed (for example, amount and currencyCode), how many components need to be built, and at which level of abstraction they need to be built (for example, a base Money component, or a ProductPrice component that makes use of the Money component).
Consider what a sensible default would be for the component. Look at various ecommerce websites and check if there is a common pattern for how this information is rendered, both on Shopify and non-Shopify storefronts. Browse through the Liquid documentation to see if there are any Liquid filters available. If there are filters available, see what those render by default and what customizations they support. Lastly, chat with UX folks to see what the best default should be.
Hydrogen must be fun and easy to use, with good ergonomics. Developer experience is very important.
Always consider how you would want to use this component if you were a developer building a custom storefront. Is the API easy to use? Which props can I pass? What are their names? Should I need to pass these props by default, or can I make use of a context to make the component easier to use? What if I don’t want to use the default? How can I customize it? Is this easy to use with JSX?
Developers should be delighted when they use headless components. To quote Tobi Lütke: “Delight works by taking your experience minus your expectation, and if the end result is a positive number, you are delighted by that margin.”
Start building. It’s likely that you might discover while hacking away that you don’t need a component at all: you might only need a hook (for example, useProductOptions) or some utilities (flattenConnection). On the other hand, you might discover that you need more components than you initially anticipated.