chore(create-next-app): add missing return types on helpers

[maxigimenez]

• Missing return types on create-next-app/helpers

[ijjk]

Stats from current PR

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General

	zeit/next.js canary	maxigimenez/next.js types/create-next-app-helpers-types	Change
buildDuration	12.1s	12.5s	⚠️ +345ms
nodeModulesSize	58.8 MB	58.8 MB	✓

Client Bundles (main, webpack, commons)

	zeit/next.js canary	maxigimenez/next.js types/create-next-app-helpers-types	Change
main-HASH.js gzip	6.23 kB	6.23 kB	✓
webpack-HASH.js gzip	746 B	746 B	✓
de003c3a9d30..5232.js gzip	10.3 kB	10.3 kB	✓
framework.HASH.js gzip	39.1 kB	39.1 kB	✓
Overall change	56.4 kB	56.4 kB	✓

Client Bundles (main, webpack, commons) Modern

	zeit/next.js canary	maxigimenez/next.js types/create-next-app-helpers-types	Change
main-HASH.module.js gzip	4.83 kB	4.83 kB	✓
webpack-HASH..dule.js gzip	746 B	746 B	✓
de003c3a9d30..dule.js gzip	6.88 kB	6.88 kB	✓
framework.HA..dule.js gzip	39.1 kB	39.1 kB	✓
Overall change	51.6 kB	51.6 kB	✓

Legacy Client Bundles (polyfills)

	zeit/next.js canary	maxigimenez/next.js types/create-next-app-helpers-types	Change
polyfills-HASH.js gzip	26.3 kB	26.3 kB	✓
Overall change	26.3 kB	26.3 kB	✓

Client Pages

	zeit/next.js canary	maxigimenez/next.js types/create-next-app-helpers-types	Change
_app.js gzip	1.23 kB	1.23 kB	✓
_error.js gzip	3.13 kB	3.13 kB	✓
hooks.js gzip	663 B	663 B	✓
index.js gzip	222 B	222 B	✓
link.js gzip	2.06 kB	2.06 kB	✓
routerDirect.js gzip	280 B	280 B	✓
withRouter.js gzip	278 B	278 B	✓
Overall change	7.86 kB	7.86 kB	✓

Client Pages Modern

	zeit/next.js canary	maxigimenez/next.js types/create-next-app-helpers-types	Change
_app.module.js gzip	598 B	598 B	✓
_error.module.js gzip	2.09 kB	2.09 kB	✓
hooks.module.js gzip	383 B	383 B	✓
index.module.js gzip	223 B	223 B	✓
link.module.js gzip	1.52 kB	1.52 kB	✓
routerDirect..dule.js gzip	279 B	279 B	✓
withRouter.m..dule.js gzip	278 B	278 B	✓
Overall change	5.37 kB	5.37 kB	✓

Client Build Manifests

	zeit/next.js canary	maxigimenez/next.js types/create-next-app-helpers-types	Change
_buildManifest.js gzip	61 B	61 B	✓
_buildManife..dule.js gzip	61 B	61 B	✓
Overall change	122 B	122 B	✓

Rendered Page Sizes

	zeit/next.js canary	maxigimenez/next.js types/create-next-app-helpers-types	Change
index.html gzip	926 B	926 B	✓
link.html gzip	936 B	936 B	✓
withRouter.html gzip	924 B	924 B	✓
Overall change	2.79 kB	2.79 kB	✓

---

Serverless Mode

General

	zeit/next.js canary	maxigimenez/next.js types/create-next-app-helpers-types	Change
buildDuration	13.6s	12.8s	-809ms
nodeModulesSize	58.8 MB	58.8 MB	✓

Client Bundles (main, webpack, commons)

	zeit/next.js canary	maxigimenez/next.js types/create-next-app-helpers-types	Change
main-HASH.js gzip	6.23 kB	6.23 kB	✓
webpack-HASH.js gzip	746 B	746 B	✓
de003c3a9d30..5232.js gzip	10.3 kB	10.3 kB	✓
framework.HASH.js gzip	39.1 kB	39.1 kB	✓
Overall change	56.4 kB	56.4 kB	✓

Client Bundles (main, webpack, commons) Modern

	zeit/next.js canary	maxigimenez/next.js types/create-next-app-helpers-types	Change
main-HASH.module.js gzip	4.83 kB	4.83 kB	✓
webpack-HASH..dule.js gzip	746 B	746 B	✓
de003c3a9d30..dule.js gzip	6.88 kB	6.88 kB	✓
framework.HA..dule.js gzip	39.1 kB	39.1 kB	✓
Overall change	51.6 kB	51.6 kB	✓

Legacy Client Bundles (polyfills)

	zeit/next.js canary	maxigimenez/next.js types/create-next-app-helpers-types	Change
polyfills-HASH.js gzip	26.3 kB	26.3 kB	✓
Overall change	26.3 kB	26.3 kB	✓

Client Pages

	zeit/next.js canary	maxigimenez/next.js types/create-next-app-helpers-types	Change
_app.js gzip	1.23 kB	1.23 kB	✓
_error.js gzip	3.13 kB	3.13 kB	✓
hooks.js gzip	663 B	663 B	✓
index.js gzip	222 B	222 B	✓
link.js gzip	2.06 kB	2.06 kB	✓
routerDirect.js gzip	280 B	280 B	✓
withRouter.js gzip	278 B	278 B	✓
Overall change	7.86 kB	7.86 kB	✓

Client Pages Modern

	zeit/next.js canary	maxigimenez/next.js types/create-next-app-helpers-types	Change
_app.module.js gzip	598 B	598 B	✓
_error.module.js gzip	2.09 kB	2.09 kB	✓
hooks.module.js gzip	383 B	383 B	✓
index.module.js gzip	223 B	223 B	✓
link.module.js gzip	1.52 kB	1.52 kB	✓
routerDirect..dule.js gzip	279 B	279 B	✓
withRouter.m..dule.js gzip	278 B	278 B	✓
Overall change	5.37 kB	5.37 kB	✓

Client Build Manifests

	zeit/next.js canary	maxigimenez/next.js types/create-next-app-helpers-types	Change
_buildManifest.js gzip	61 B	61 B	✓
_buildManife..dule.js gzip	61 B	61 B	✓
Overall change	122 B	122 B	✓

Serverless bundles

	zeit/next.js canary	maxigimenez/next.js types/create-next-app-helpers-types	Change
_error.js	853 kB	853 kB	✓
404.html	4.18 kB	4.18 kB	✓
hooks.html	3.81 kB	3.81 kB	✓
index.js	853 kB	853 kB	✓
link.js	891 kB	891 kB	✓
routerDirect.js	883 kB	883 kB	✓
withRouter.js	884 kB	884 kB	✓
Overall change	4.37 MB	4.37 MB	✓

[lfades]

Hi @maxigimenez thank you for the PR!. The types added here aren't required as TypeScript can infer the boolean type in all of this cases, therefore we don't have to define them ourselves!

[maxigimenez]

@lfades thanks! I was reading the source code, to get a bit familiar and notice several places where : Promise<boolean> (and similar with booleans) is being used, that's why I open the PR 😄

[timneutkens]

Looks like a pretty great PR to land actually, I can't bring back the branch though so can you re-open this PR @maxigimenez

[maxigimenez]

@timneutkens branch restored, maybe you can re-open this PR

[maxigimenez]

I'm up for either remove these types or add more if you guys agree. These are easy things to spot on my way to get familiar with the source code.