Feature : Export a function to get typeChecker

[Lookwe69]

I could be nice to be able to call a function to get the typescript typechecker. It can be useful when we write custom cem plugin that need tsTypeChecker.

[break-stuff]

I have internal configurations as well as configuration form the plugin that may not be needed for everything, so it may not be what you want. Can you provide an example of what you would like to use it for?

[Lookwe69]

I use the typeChecker to build a custom plugin to auto detect css vars for my project. The typeChecker is needed to retrieve the import path from styles variable.

import type { CSSResultOrNative } from 'lit';
import { customElement } from 'lit/decorators.js';

import { Button } from './internal/button.js';
import styles from './internal/button.styles.scss';

@customElement('gui-button')
export class GuiButton extends Button {
	static override styles: CSSResultOrNative[] = [...super.styles, styles];
}

Plugin (e.g.)

function handleCSSProperties(ts, checker, classNode, moduleDoc, transformPath) {
	const className = classNode.name?.getText();

	const currClass = moduleDoc?.declarations?.find((declaration) => declaration.name === className);

	classNode.members?.forEach((member) => {
		if (!isStaticStyles(ts, member)) return;

		const propertyInitializer = member.initializer;
		if (propertyInitializer && ts.isArrayLiteralExpression(propertyInitializer)) {
			const identifiers = propertyInitializer.elements.filter((element) => ts.isIdentifier(element));
			identifiers.forEach((identifier) => {
				const originalNode = checker.getSymbolAtLocation(identifier);
				const parent = originalNode.declarations[0]?.parent;
				if (parent && ts.isImportDeclaration(parent)) {
					const modulePath = parent.moduleSpecifier.getText().replaceAll(/['"]/g, '');
					if (typeof modulePath === 'string' && modulePath.endsWith('.scss')) {
						const filePath = transformPath(path.join(path.dirname(moduleDoc.path), modulePath));

						const result = sass.compile(filePath);
						analyzeCSS(result.css, currClass);
					}
				}
			});
		}
	});
}