initial commit

src/jsx.ts

@@ -0,0 +1,123 @@
+/**
+ * Copyright (c) 2025 favewa
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+import { Attrs, escape, html, VOID_TAGS } from "./html.ts";
+import { ChunkedStream } from "./stream.ts";
+
+export const Fragment = Symbol("Fragment");
+
+type Props = Attrs & { children?: any };
+type Component = (props: Props) => JsxElement | AsyncGenerator<JsxElement>;
+
+export type JsxElement =
+  | ((chunks: ChunkedStream<string>) => Promise<void>)
+  | AsyncGenerator<JsxElement, void, unknown>;
+
+async function render(
+  child: any,
+  chunks: ChunkedStream<string>,
+  context: ReturnType<typeof html>,
+): Promise<void> {
+  if (child == null || child === false || child === true) return;
+
+  if (typeof child === "string") return chunks.write(escape(child));
+  if (typeof child === "number") return chunks.write(String(child));
+
+  if (typeof child === "function") return await child(chunks);
+  if (child instanceof Promise) {
+    return await render(await child, chunks, context);
+  }
+
+  if (typeof child === "object" && Symbol.asyncIterator in child) {
+    (async () => {
+      for await (const item of child) {
+        await render(item, chunks, context);
+      }
+    })();
+    return;
+  }
+
+  if (Array.isArray(child)) {
+    for (const item of child) await render(item, chunks, context);
+    return;
+  }
+
+  chunks.write(escape(String(child)));
+}
+
+export function jsx(
+  tag: string | Component | typeof Fragment,
+  props: Props | null = {},
+): JsxElement {
+  props ||= {};
+
+  return async (chunks: ChunkedStream<string>) => {
+    const context = html(chunks);
+    const { children, ...attrs } = props;
+
+    if (tag === Fragment) {
+      if (!Array.isArray(children)) {
+        return await render([children], chunks, context);
+      }
+      for (const child of children) {
+        await render(child, chunks, context);
+      }
+      return;
+    }
+
+    if (typeof tag === "function") {
+      return await render(tag(props), chunks, context);
+    }
+
+    const childr = children == null ? [] : [].concat(children);
+    const attributes = Object.keys(attrs).length ? attrs : {};
+
+    if (!childr.length || VOID_TAGS.has(tag)) {
+      await context[tag](childr);
+    } else {
+      await context[tag](attributes, async () => {
+        for (const child of childr) {
+          await render(child, chunks, context);
+        }
+      });
+    }
+  };
+}
+
+export const jsxs = jsx;
+
+async function renderJsx(
+  element: JsxElement | JsxElement[],
+  chunks: ChunkedStream<string>,
+): Promise<void> {
+  if (Array.isArray(element)) {
+    for (const el of element) {
+      await renderJsx(el, chunks);
+    }
+    return;
+  }
+  if (typeof element === "object" && Symbol.asyncIterator in element) {
+    for await (const item of element) {
+      await renderJsx(item, chunks);
+    }
+    return;
+  }
+  if (typeof element === "function") {
+    await element(chunks);
+  }
+}
+
+export const raw =
+  (html: string): JsxElement =>
+  async (chunks: ChunkedStream<string>) =>
+    void (!chunks.closed && chunks.write(html));
+
+export const open = <K extends keyof HTMLElementTagNameMap>(tag: K) =>
+  raw(`<${tag}>`);
+
+export const close = <K extends keyof HTMLElementTagNameMap>(tag: K) =>
+  raw(`</${tag}>`);
+
+export { renderJsx as render };