quick-lint-js

Find bugs in JavaScript programs.

E0267: TypeScript types are not allowed in JavaScript

TypeScript type aliases can be declared with the type keyword. It is a syntax error to write a TypeScript type alias in JavaScript code:

type Response<T> = {
  ok: boolean;
  error?: string;
  data?: T;
};

To fix this error, rename your file to have a .ts or .tsx suffix.

Alternatively, use JSDoc to declare the type:

/**
 * @typedef {Object} Response
 * @prop {boolean} ok
 * @prop {string} [error]
 * @prop {Object} data
 */

Documentation for other errors