No errors for TypeScript `import` types

[OliverJAsh]

Docs on import types: https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-9.html#import-types

Reduced test case (all dependencies are latest):

// ./cypress/test.ts

// Expected error, got one
// Unexpected path "../app/helpers/api" imported in restricted zone
import Api from '../app/helpers/api';

// Expected error, but got none
type Api = typeof import('../app/helpers/api');

// .eslintrc.js
const config = {
  extends: ['plugin:import/typescript'],
  parser: '@typescript-eslint/parser',
  parserOptions: {
    ecmaVersion: 6,
    sourceType: 'module',
  },
  plugins: ['import'],
  rules: {
    'import/no-restricted-paths': [
      2,
      {
        basePath: '.',
        zones: [
          {
            target: './cypress',
            from: './app',
          },
        ],
      },
    ],
  },
}

module.exports = config;

[ljharb]

This isn't a TypeScript thing, import() is a language feature, dynamic import. That it's in type-space is unrelated.

Dynamic imports aren't usually checked, because they aren't forced to be static, and it's impossible to reliably statically know the import path.

[OliverJAsh]

Good point.

Dynamic imports aren't usually checked, because they aren't forced to be static, and it's impossible to reliably statically know the import path.

When using them at the type-level, they are required to be static, so it does makes sense to lint them in this context.

[ljharb]

At that point tho, doesn't typescript itself warn on it?

[OliverJAsh]

Why would TS warn about this?

type Api = typeof import('../app/helpers/api');

The module path is valid. It's just we want to disallow it, via no-restricted-paths.

[ljharb]

ahhh gotcha, thanks for clarifying.

[Baumgaer]

I am feeling free to ask for an additional parameter for each zone.

Is it possible to allow typescript special imports for types?

import type {MyType} from "/normally/forbidden/import/in/restricted/area"

It would be nice to disallow imports which stay in compiled javascript but allow imports of type in this way. The parameter for the zone could be named as "allowTypeImports": true

[fregante]

None of these run any code so they should be allowed:

import "/normally/forbidden/import/in/restricted/area" // if the file is d.ts, but rare
import {MyType} from "/normally/forbidden/import/in/restricted/area"
import {type MyType} from "/normally/forbidden/import/in/restricted/area"
import type {MyType} from "/normally/forbidden/import/in/restricted/area"
type MyType = typeof import("/normally/forbidden/import/in/restricted/area");