Partial

partial of a type: accept any subset

Make properties of an existing type optional, creating a new type. Conforming objects may contain any subset of the original properties:

interface SearchConfig {
    query: string
    inStock: boolean
    minPrice: number
    maxPrice: number
}

const searchConfig: Partial<SearchConfig> = {
    query: "RTX 5060",
    inStock: true,
}

example: typing merge update data

When updating an existing record with a merge strategy, we only provide the properties to be changed, that is, a subset of the original record:

type ProductUpdate = Partial<Product>

(advanced) Note: if the update should not affect some properties because they are immutable, we either:

• white-list the mutable properties that can be included in the update object with Pick:

type ProductUpdate = Partial<Pick<Product, "price" | "description">>

• exclude the immutable properties with Omit:

type ProductUpdate = Partial<Omit<Product, "id" | "slug">>