Pick⟨Type, Keys⟩ Utility Type in TypeScript
What is Pick⟨Type, Keys⟩ in TypeScript
Pick⟨Type, Keys⟩ is a utility type in TypeScript that creates a new type by selecting specific properties from an existing type.
In simple terms:
It takes an object type and keeps only the properties you choose.
Basic idea
Conceptually:
Pick⟨Type, Keys⟩
means:
Create a new type with only Keys from Type
Simple example
type User = {
id: number;
name: string;
email: string;
isAdmin: boolean;
};
type UserPreview = Pick⟨User, "id" | "name"⟩;
const user: UserPreview = {
id: 1,
name: "Alice",
};
Resulting type:
id is included
name is included
email is removed
isAdmin is removed
What happens if you add extra properties
const user: UserPreview = {
id: 1,
name: "Alice",
email: "[email protected]",
};
// Error: property "email" does not exist
Pick is strict: only the selected keys are allowed.
Very common use cases
1. API responses
type PublicUser = Pick⟨User, "id" | "name"⟩;
Expose only safe fields to the frontend or external clients.
2. Component props in React
type UserCardProps = Pick⟨User, "name" | "email"⟩;
Reuse existing types without duplicating definitions.
3. Reducing large types
type UserFlags = Pick⟨User, "isAdmin"⟩;
Extract just what you need for a specific use case.
How Pick works internally (mental model)
You can think of it like this:
type Pick⟨T, K extends keyof T⟩ = {
[Key in K]: T[Key];
};
Meaning:
Loop over each key in Keys
Copy that property from Type
Ignore everything else
Pick vs Partial
These are often combined but do different things:
Pick⟨Type, Keys⟩ → selects properties
Partial⟨Type⟩ → makes properties optional
Example:
type EditableUser = Partial⟨Pick⟨User, "name" | "email"⟩⟩;
This means:
Only name and email
Both are optional
Pick vs Omit
Pick⟨Type, Keys⟩ → choose what to keep
Omit⟨Type, Keys⟩ → choose what to remove
Example:
type UserWithoutEmail = Omit⟨User, "email"⟩;
Both are valid; Pick is often clearer when selecting a small subset.
Important things to know
1. Keys must exist on the type
Pick⟨User, "age"⟩;
// Error: "age" is not a key of User
TypeScript protects you from typos and invalid keys.
2. Pick is shallow
It only picks top-level properties, not nested ones.
When to use Pick⟨Type, Keys⟩
Use it when:
You want a subset of an existing type
You want to avoid duplicating type definitions
You want stricter, smaller object shapes
Avoid it when:
You need to transform property types
You need deep selection logic
One‑line summary
Pick⟨Type, Keys⟩ creates a new type with only the selected properties from Type.