Deriving a smaller type from a big interface with Pick

I keep copying my interface and deleting fields by hand.

Intermediate to advancedRead 8 minDoing: under an hour7 steps

▶ Start

What you'll have at the end

A derived type with only the fields the form needs, that updates itself if the source changes

Before you start

You need

An interface or type alias describing a full object shape, and at least one place in the code that only needs some of its fields.

Not covered

Restructuring the fields inside the base interface itself, or deciding whether that base shape should be an interface or a type alias in the first place.

Leans on

TypeScript Cheat SheetIts Utility Types table covers Pick, Omit and Partial together, and its Type Operators table explains keyof, the mechanism that makes Pick check its key list at all.
JavaScript Cheat SheetIts Destructuring, Spread and Patterns table covers pulling exactly the fields a derived type names out of a real object once the type itself is settled.

7 steps

Where to go next

Interface or type alias: make the call

for deciding whether the base shape belongs to an interface or a type alias before you derive anything smaller from it

Checked 22 Aug 2026

Part of the TypeScript cookbook