Improve emitted type declarations for TS 5.5+

[Fryuni]

Some changes in TS 5.5 caused the declarations emitted from our inferred types to include internal types, both ours and from Astro. This causes

Example

Take this simplified example from Inox Tools as a base:

export const runtimeLogger = defineUtility('astro:config:setup')((
	params: HookParameters<'astro:config:setup'>,
	options: { name: string }
) => {
	// do something
});

export default defineIntegration({
	name: '@inox-tools/runtime-logger',
	setup: () => ({
		hooks: {
			'astro:config:setup': (params) => {
				// do something
			},
		},
		something: (it: string): string => it,
	}),
});

With the new TS version, the following type declaration is emitted:

import * as astro from 'astro';
import { AstroIntegrationLogger } from 'astro';

type Prettify<T> = {
    [K in keyof T]: T[K];
} & {};

type DeepPartial<T> = {
    [P in keyof T]?: T[P] extends (infer U)[] ? DeepPartial<U>[] : T[P] extends object | undefined ? DeepPartial<T[P]> : T[P];
};

declare const runtimeLogger: (params: {
    config: astro.AstroConfig;
    command: "dev" | "build" | "preview";
    isRestart: boolean;
    updateConfig: (newConfig: DeepPartial<astro.AstroConfig>) => astro.AstroConfig;
    addRenderer: (renderer: astro.AstroRenderer) => void;
    addWatchFile: (path: URL | string) => void;
    injectScript: (stage: astro.InjectedScriptStage, content: string) => void;
    injectRoute: (injectRoute: astro.InjectedRoute) => void;
    addClientDirective: (directive: astro.ClientDirectiveConfig) => void;
    addDevOverlayPlugin: (entrypoint: string) => void;
    addDevToolbarApp: (entrypoint: astro.DevToolbarAppEntry | string) => void;
    addMiddleware: (mid: astro.AstroIntegrationMiddleware) => void;
    logger: AstroIntegrationLogger;
}, options: {
    name: string;
}) => void;
declare const _default: () => astro.AstroIntegration & Prettify<Omit<ReturnType<() => {
    hooks: {
        'astro:config:setup': (params: {
            config: astro.AstroConfig;
            command: "dev" | "build" | "preview";
            isRestart: boolean;
            updateConfig: (newConfig: DeepPartial<astro.AstroConfig>) => astro.AstroConfig;
            addRenderer: (renderer: astro.AstroRenderer) => void;
            addWatchFile: (path: URL | string) => void;
            injectScript: (stage: astro.InjectedScriptStage, content: string) => void;
            injectRoute: (injectRoute: astro.InjectedRoute) => void;
            addClientDirective: (directive: astro.ClientDirectiveConfig) => void;
            addDevOverlayPlugin: (entrypoint: string) => void;
            addDevToolbarApp: (entrypoint: astro.DevToolbarAppEntry | string) => void;
            addMiddleware: (mid: astro.AstroIntegrationMiddleware) => void;
            logger: AstroIntegrationLogger;
        }) => void;
    };
    something: (it: string) => string;
}>, keyof astro.AstroIntegration>>;

export { _default as default, runtimeLogger };

With the optimization the following declaration is emitted:

import * as astro from 'astro';
import * as astro_integration_kit from 'astro-integration-kit';

declare const runtimeLogger: astro_integration_kit.HookUtility<"astro:config:setup", [options: {
    name: string;
}], void>;
declare const _default: () => astro.AstroIntegration & {
    something: (it: string) => string;
};

export { _default as default, runtimeLogger };

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[Adammatthiesen]

Neat. so much cleaner....

[florian-lefebvre]

what does this do?

[Fryuni]

It is a TS trick to force a generic to expand to its component types.