Utilities

1. Partial

Partials can be used to make properties on an interface as optional. For example, if we have an existing interface with three properties and we want to create an object with some of those properties (not all the properties), then we have to create a new interface or make some of the properties as optionals for doing so.

Instead, we can use Partial utility type in TypeScript which will help us acheive the same.

interface IProps {
  prop1: string,
  prop2: boolean,
  prop3: number[]
}

// Object with all the properties.
const object = {
  prop1: "Shaan Alam",
  prop2: true,
  prop3: [19, 27]
}

// Object with some of the properties.
const object2: Partial<IProps> = {
  prop1: "John Doe",
  prop3: [34, 56]
}

2. Omit

We can also omit some properties from an interface using Omit utility type.

interface IProps {
  prop1: string,
  prop2: boolean,
  prop3: number[]
}

// To omit a single property
const object: Omit<IProps, "prop2"> = {
  prop1: "Shaan Alam",
  prop3: [21, 78]
}

// To omit multiple property
const object2: Omit<IProps, "prop2" | "prop3"> = {
  prop1: "Shaan Alam"
}