Миграция большого проекта с JavaScript

{
  "compilerOptions": {
    "allowJs": true,
    "checkJs": false
  }
}

// @ts-check
function add(a, b) { return a + b; }

// Фрагмент для анализа
// @ts-nocheck

/** @param {string} id */
function loadUser(id) {}

/** @param {import("./types").UserId} id */
function load(id) {}

{
  "allowJs": true,
  "declaration": true,
  "emitDeclarationOnly": true
}

declare const legacy: any;
const user = legacy.load();
const name = user.profile.name;

function parseLegacy(input: string): DomainResult {
  const raw: unknown = legacy.parse(input);
  return decodeDomainResult(raw);
}

// @ts-expect-error — legacy callback has wrong declaration, issue #418
legacy.on("data", handler);

tsc --noEmit --pretty false

// @ts-expect-error — временно до обновления types
legacyCall(1);

import { createClient } from "../src/client";
const client = createClient({ timeoutMs: 100 });

// @ts-check
/**
 * @param {string} id
 * @param {(user: {id: string, name: string}) => void} done
 */
export function loadUser(id, done) { /* legacy body */ }

// @ts-check
/** @param {string} id */
function loadUser(id) {}

const raw = JSON.parse(source);
// Небезопасно: const user = raw as User;

export interface UserGateway {
  load(id: UserId): Promise<UserSummary | undefined>;
}

const legacyUser = { id: "", name: "", cacheState: {} };
export type PublicUser = typeof legacyUser;

interface LoadOptions { locale?: string; signal?: AbortSignal; }
declare function loadUser(id: string, options?: LoadOptions): Promise<UserSummary>;