Assert Never npm version

Helper function for exhaustive checks of discriminated unions in TypeScript.

Installation

npm install --save assert-never

Usage

import {assertNever} from "assert-never";

type A = {type: 'a'};
type B = {type: 'b'};
type Union = A | B;

function doSomething(arg: Union) {
  if (arg.type === 'a') {
    return something;
  }

  if (arg.type === 'b') {
    return somethingElse;
  }

  // TS will error if there are other types in the union
  // Will throw an Error when called at runtime. Use `assertNever(arg, true)`
  // instead to fail silently.
  return assertNever(arg);
}

Assert Never

Helper function for exhaustive checks of discriminated unions in TypeScript

Assert Never Info

⭐ Stars 18
🔗 Source Code github.com
🕒 Last Update a year ago
🕒 Created 5 years ago
🐞 Open Issues 0
➗ Star-Issue Ratio Infinity
😎 Author aikoven