svelte/src/generators/server-side-rendering/index.ts

import deindent from '../../utils/deindent';
import Generator from '../Generator';
import Block from './Block';
import visit from './visit';
import { Parsed, Node, CompileOptions } from '../../interfaces';

export class SsrGenerator extends Generator {
	bindings: string[];
	renderCode: string;
	elementDepth: number;

	constructor(
		parsed: Parsed,
		source: string,
		name: string,
		options: CompileOptions
	) {
		super(parsed, source, name, options);
		this.bindings = [];
		this.renderCode = '';
		this.elementDepth = 0;
	}

	append(code: string) {
		this.renderCode += code;
	}
}

export default function ssr(
	parsed: Parsed,
	source: string,
	options: CompileOptions
) {
	const format = options.format || 'cjs';
	const name = options.name || 'SvelteComponent';

	const generator = new SsrGenerator(parsed, source, name, options);

	const { computations, hasJs, templateProperties } = generator.parseJs(true);

	// create main render() function
	const mainBlock = new Block({
		generator,
		contexts: new Map(),
		indexes: new Map(),
		conditions: [],
	});

	parsed.html.children.forEach((node: Node) => {
		visit(generator, mainBlock, node);
	});

	const result = deindent`
		${hasJs && `[✂${parsed.js.content.start}-${parsed.js.content.end}✂]`}

		var ${name} = {};

		${name}.filename = ${JSON.stringify(options.filename)};

		${name}.data = function () {
			return ${templateProperties.data
				? `@template.data()`
				: `{}`};
		};

		${name}.render = function ( state, options ) {
			${templateProperties.data
				? `state = Object.assign( @template.data(), state || {} );`
				: `state = state || {};`}

			${computations.map(
				({ key, deps }) =>
					`state.${key} = @template.computed.${key}( ${deps.map(dep => `state.${dep}`).join(', ')} );`
			)}

			${generator.bindings.length &&
				deindent`
				var settled = false;
				var tmp;

				while ( !settled ) {
					settled = true;

					${generator.bindings.join('\n\n')}
				}
			`}

			return \`${generator.renderCode}\`;
		};

		${name}.renderCss = function () {
			var components = [];

			${generator.css &&
				deindent`
				components.push({
					filename: ${name}.filename,
					css: ${JSON.stringify(generator.css)},
					map: null // TODO
				});
			`}

			${templateProperties.components &&
				deindent`
				var seen = {};

				function addComponent ( component ) {
					var result = component.renderCss();
					result.components.forEach( x => {
						if ( seen[ x.filename ] ) return;
						seen[ x.filename ] = true;
						components.push( x );
					});
				}

				${templateProperties.components.value.properties.map(prop => {
					const { name } = prop.key;
					const expression =
						generator.importedComponents.get(name) ||
						`@template.components.${name}`;
					return `addComponent( ${expression} );`;
				})}
			`}

			return {
				css: components.map( x => x.css ).join( '\\n' ),
				map: null,
				components
			};
		};

		var escaped = {
			'"': '"',
			"'": ''',
			'&': '&',
			'<': '&lt;',
			'>': '&gt;'
		};

		function __escape ( html ) {
			return String( html ).replace( /["'&<>]/g, match => escaped[ match ] );
		}
	`.replace(/@(\w+)/g, (match, name) => generator.alias(name));

	return generator.generate(result, options, { name, format });
}