Readonly type breaks Set and Map

TypeScript Version: 3.4.0-dev.201xxxxx

Search Terms:

Code

// A *self-contained* demonstration of the problem follows...
// Test this by running `tsc` on the command-line, rather than through another build tool such as Gulp, Webpack, etc.

Expected behavior:

However, Set and Map can't use with es3 and es5. We need any workaround.

export type Readonly<T> =
  T extends ReadonlySet<infer V> ? ReadonlySet<V> :
  T extends ReadonlyMap<infer K, infer V> ? ReadonlyMap<K, V> :
  { readonly [P in keyof T]: T[P]; };

Actual behavior:

type Readonly<T> = {
    readonly [P in keyof T]: T[P];
};

Playground Link:

Related Issues:

未指定 repository 文件或测试。首先将提供的 Readonly 片段缩减为一个可复现的 TypeScript 示例，并使用 tsc 运行；当 ES3/ES5 的预期 Set 和 Map 行为得到清晰复现，并由适当的编译器测试覆盖时，即视为完成。