quick-lint-js

Find bugs in JavaScript programs.

E0213: TypeScript's 'interface' feature is not allowed in JavaScript code

JavaScript does not support interfaces. It is a syntax error to write a TypeScript interface in JavaScript code:

interface 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 interface:

/**
 * @typedef {Object} Response - creates a new type named 'SpecialType'
 * @prop {boolean} ok
 * @prop {string} [error] - a number property of SpecialType
 * @prop {Object} data
 */

Documentation for other errors