ts-hover-prettify

Provide Prettify<T> so TypeScript hovers show a single object shape instead of a chain of intersections.

What is this?

This package exports the Prettify<T> utility type for projects where you want the type in source control or need tsc / CI without the VS Code extension. The extension injects the same type automatically — pick one approach per repo.

The mapped-type pattern only affects how TypeScript prints types in the language service. It is erased at compile time and does not change JavaScript output.

Quick Start

pnpm add -D ts-hover-prettify
# npm add -D ts-hover-prettify
# yarn add -D ts-hover-prettify

Global Prettify (recommended)

Create a declaration file included by your tsconfig.json, for example prettify.d.ts:

import "ts-hover-prettify/global";

Add it to compilerOptions.types, or to top-level include / files:

{
  "include": ["src/**/*", "prettify.d.ts"]
}

After that, Prettify is available everywhere in the project without importing it in each file.

Named import

import type { Prettify } from "ts-hover-prettify";

type Flat = Prettify<{ x: 1 } & { y: 2 }>;

Example

type Intersected = { a: string } & { b: number } & { c: boolean };
// Hover: { a: string; } & { b: number; } & { c: boolean; }

type Readable = Prettify<
  { a: string } & { b: number } & { c: boolean }
>;
// Hover: { a: string; b: number; c: boolean; }

Working example in this repo: examples/intersected-types-npm. Verify from the repo root:

pnpm verify:example-npm

API

export type Prettify<T> = {
  [K in keyof T]: T[K];
} & {};

Implementation matches the common community pattern (also documented as Compute, Expand, etc.).

Behaviour and limits

• Wrap only the types where you care about hover readability. Unwrapped aliases keep their default display.
• Works best on object intersections and similar shapes you intentionally pass into Prettify. It does not recursively “fix” every nested type in the project.
• Requires TypeScript (peer usage via your project’s typescript version). This package ships type definitions only; it does not patch the compiler.

VS Code / Cursor without npm

Use the ts-hover-prettify-vscode extension instead of this package if you only need editor hovers and accept workspace injection of .vscode/ts-hover-prettify.d.ts.

Documentation

| Resource | Description | |----------|-------------| | Root README | Monorepo overview and install options | | Extension README | Zero-config editor setup | | CHANGELOG.md | Package release notes |

Contributing

Issues and pull requests are welcome on GitHub.

License

MIT — Copyright 2023 Marco Antolini.