unresolvableTypes

ngtrue/node

Every subpath whose types do not resolve, under each module-resolution mode, as one sentence each. An empty array is a pass.

A runnable example

import { unresolvableTypes } from 'ngtrue/node';

it('resolves its types the way a consumer will', async () => {
  expect(await unresolvableTypes({ packageDir: 'dist' })).toEqual([]);
});

Narrow it while iterating:

await unresolvableTypes({ packageDir: 'dist', modes: ['node16'] });

How it answers

It runs TypeScript's own resolver — the same ts.resolveModuleName call tsc and your editor make — against a throwaway directory with the package symlinked into node_modules.

Nothing about the resolution is reimplemented, and that matters more here than anywhere else in ngtrue. The rules are intricate: condition ORDER decides the answer, types has to precede import, a missing types falls through to the JavaScript without a word, and the whole thing differs per mode. An approximation of that would agree with the real resolver on every package that was already correct, which is the definition of a check that cannot fail.

Probing through a symlinked node_modules rather than through TypeScript's self-reference support is deliberate too: a consumer resolves the package from node_modules, and that is the layout whose answer matters.

Both modes, because your consumers are not all you

bundler is forgiving in ways node16 is not. A package checked only under the mode its own repository happens to use will still break for half the people who install it, and it will break at their tsc, not yours.

Resolving to JavaScript is a finding

Louder than resolving to nothing, in fact. A subpath that resolves to a .js with no declarations beside it hands the consumer any, with no error — the package appears to work right up until something that should not have compiled ships. The two are distinguished in the message because they have different fixes.

What it does not check

Wildcard subpaths are skipped, and the skip is reported. Each stands for an open set and a single sample would say nothing about the rest. It appears in the returned array so it cannot be mistaken for a pass.

Only the conditions the package declares are probed. An ESM-only package has no require branch, and reporting one missing would be reporting a design decision as a defect. Whether a package IS dual is a question about the manifest, and unresolvedExports is where the manifest is the subject.

typescript must be installed. It is an optional peer of ngtrue and this is the only export that needs it. Any repository shipping a typed package has it; one that somehow does not gets an error saying so, rather than a pass.