Simplify

Flattens an intersection or mapped type into a single, flat object type. The type is the same, but editors show it as { a: 1; b: 2 } instead of A & B.

type Flat = Simplify<T>;

Usage

Simplify<T>

An intersection (&) left as-is shows up as A & B in editor tooltips, which makes the real shape hard to read. Wrapping it in Simplify expands the final properties into one object. The ? (optional) and readonly markers are preserved.

import type { Simplify } from 'es-toolkit/types';

type A = { name: string };
type B = { readonly age?: number };

// Without wrapping, the tooltip shows 'A & B'.
type Raw = A & B;

// Simplify expands it into one object. The ? and readonly markers are kept.
type User = Simplify<A & B>;
// => { name: string; readonly age?: number }

Type Parameters

• T: The type to flatten.