svelte/src/generators/server-side-rendering/visitors/Element.ts

import visitComponent from './Component';
import isVoidElementName from '../../../utils/isVoidElementName';
import visit from '../visit';
import visitWindow from './meta/Window';
import { SsrGenerator } from '../index';
import Block from '../Block';
import { Node } from '../../../interfaces';

const meta = {
	':Window': visitWindow
};

function stringifyAttributeValue ( block: Block, chunks: Node[] ) {
	return chunks.map( ( chunk: Node ) => {
		if ( chunk.type === 'Text' ) {
			return chunk.data;
		}

		const { snippet } = block.contextualise( chunk.expression );
		return '${' + snippet + '}';
	}).join( '' )
}

export default function visitElement ( generator: SsrGenerator, block: Block, node: Node ) {
	if ( node.name in meta ) {
		return meta[ node.name ]( generator, block, node );
	}

	if ( generator.components.has( node.name ) || node.name === ':Self' ) {
		visitComponent( generator, block, node );
		return;
	}

	let openingTag = `<${node.name}`;
	let textareaContents; // awkward special case

	node.attributes.forEach( ( attribute: Node ) => {
		if ( attribute.type !== 'Attribute' ) return;

		if ( attribute.name === 'value' && node.name === 'textarea' ) {
			textareaContents = stringifyAttributeValue( block, attribute.value );
		} else {
			let str = ` ${attribute.name}`;

			if ( attribute.value !== true ) {
				str += `="${stringifyAttributeValue( block, attribute.value )}"`;
			}

			openingTag += str;
		}
	});

	if ( generator.cssId && !generator.elementDepth ) {
		openingTag += ` ${generator.cssId}`;
	}

	openingTag += '>';

	generator.append( openingTag );

	if ( node.name === 'textarea' && textareaContents !== undefined ) {
		generator.append( textareaContents );
	} else {
		generator.elementDepth += 1;

		node.children.forEach( ( child: Node ) => {
			visit( generator, block, child );
		});

		generator.elementDepth -= 1;
	}

	if ( !isVoidElementName( node.name ) ) {
		generator.append( `</${node.name}>` );
	}
}