80 lines
2 KiB
JavaScript
80 lines
2 KiB
JavaScript
import './server-shim.js';
|
||
import '@lit-labs/ssr/lib/render-lit-html.js';
|
||
import { LitElementRenderer } from '@lit-labs/ssr/lib/lit-element-renderer.js';
|
||
|
||
function isCustomElementTag(name) {
|
||
return typeof name === 'string' && /-/.test(name);
|
||
}
|
||
|
||
function getCustomElementConstructor(name) {
|
||
if (typeof customElements !== 'undefined' && isCustomElementTag(name)) {
|
||
return customElements.get(name) || null;
|
||
} else if (typeof name === 'function') {
|
||
return name;
|
||
}
|
||
return null;
|
||
}
|
||
|
||
async function isLitElement(Component) {
|
||
const Ctr = getCustomElementConstructor(Component);
|
||
return !!(Ctr && Ctr._$litElement$);
|
||
}
|
||
|
||
async function check(Component, _props, _children) {
|
||
// Lit doesn't support getting a tagName from a Constructor at this time.
|
||
// So this must be a string at the moment.
|
||
return !!(await isLitElement(Component));
|
||
}
|
||
|
||
function* render(Component, attrs, children) {
|
||
let tagName = Component;
|
||
if (typeof tagName !== 'string') {
|
||
tagName = Component[Symbol.for('tagName')];
|
||
}
|
||
const instance = new LitElementRenderer(tagName);
|
||
|
||
// LitElementRenderer creates a new element instance, so copy over.
|
||
const Ctr = getCustomElementConstructor(tagName);
|
||
if (attrs) {
|
||
for (let [name, value] of Object.entries(attrs)) {
|
||
// check if this is a reactive property
|
||
if (name in Ctr.prototype) {
|
||
instance.setProperty(name, value);
|
||
} else {
|
||
instance.setAttribute(name, value);
|
||
}
|
||
}
|
||
}
|
||
|
||
instance.connectedCallback();
|
||
|
||
yield `<${tagName}`;
|
||
yield* instance.renderAttributes();
|
||
yield `>`;
|
||
const shadowContents = instance.renderShadow({});
|
||
if (shadowContents !== undefined) {
|
||
yield '<template shadowroot="open">';
|
||
yield* shadowContents;
|
||
yield '</template>';
|
||
}
|
||
yield children || ''; // don’t print “undefined” as string
|
||
yield `</${tagName}>`;
|
||
}
|
||
|
||
async function renderToStaticMarkup(Component, props, children) {
|
||
let tagName = Component;
|
||
|
||
let out = '';
|
||
for (let chunk of render(tagName, props, children)) {
|
||
out += chunk;
|
||
}
|
||
|
||
return {
|
||
html: out,
|
||
};
|
||
}
|
||
|
||
export default {
|
||
check,
|
||
renderToStaticMarkup,
|
||
};
|