fix (core): allow falsy values in astro config integrations arrays

[cameronmcefee]

Changes

TL;DR: this updates the astro config type to allow falsy values in the integrations array, which the docs indicate should be possible. Related: withastro/docs#1334

---

The docs state:

Falsy integrations are ignored, so you can toggle integrations on & off without worrying about left-behind undefined and boolean values.

integrations: [
  // Example: Skip building a sitemap on Windows
  process.platform !== 'win32' && sitemap()
]

However, Typescript will generate the following error if you try to do this:

Type 'false | AstroIntegration' is not assignable to type 'AstroIntegration | AstroIntegration[]'.

In this particular change, I've chosen a nullish interpretation of "falsy" allowing false, null, and undefined. I'm happy to update to a more conservative false only solution, which might read more cleanly.

Based on the schema in https://github.com/withastro/astro/blob/main/packages/astro/src/core/config.ts#L139, I believe this is a safe change, as the looser type will still conform to the validation format due to the filter(Boolean) preprocessing.

I'm in a bit over my head with the contribution formula here, so holler at me if I've done something wrong or there's a better way to handle this.

Testing

Tests are not included because I couldn't get them to fully run locally with a fresh install prior to making this change. I'm hoping the PR checks will run the appropriate checks, at which point I'll update.

Docs

There are no changes to the docs, as this change brings the codebase inline with what the docs already state.

[changeset-bot]

🦋 Changeset detected

Latest commit: 6af81c3

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 14 packages

Name	Type
astro	Patch
@e2e/astro-component	Patch
@e2e/error-react-spectrum	Patch
@e2e/error-sass	Patch
@e2e/errors	Patch
@e2e/hydration-race	Patch
@e2e/lit-component	Patch
@e2e/preact-component	Patch
@e2e/react-component	Patch
@e2e/solid-component	Patch
@e2e/solid-recurse	Patch
@e2e/svelte-component	Patch
@e2e/e2e-tailwindcss	Patch
@e2e/ts-resolution	Patch

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[matthewp]

We have an existing test that the functionality works:

astro/packages/astro/test/config-validate.test.js

Lines 42 to 48 in a2414bf

	it('ignores falsey "integration" values', async () => {
	const result = await validateConfig(
	{ integrations: [0, false, null, undefined] },
	process.cwd()
	);
	expect(result.integrations).to.deep.equal([]);
	});

So this PR simply fixes the types. Thank you.