htmlrewriter/dist/html_rewriter_wrapper.js

Use Cloudflare HTMLRewriter in Node.js, Browser, Next.js and more

import { HTMLRewriter as RawHTMLRewriter } from '../dist/html_rewriter.js';
const encoder = new TextEncoder();
const decoder = new TextDecoder();
// console.log(wasm)
class HTMLRewriter {
    constructor(options = {}) {
        this.elementHandlers = [];
        this.documentHandlers = [];
    }
    on(selector, handlers) {
        this.elementHandlers.push([selector, handlers]);
        return this;
    }
    onDocument(handlers) {
        this.documentHandlers.push(handlers);
        return this;
    }
    transform(response) {
        const body = response.body;
        // HTMLRewriter doesn't run the end handler if the body is null, so it's
        // pointless to setup the readable stream.
        if (body === null)
            return new Response(body, response);
        if (response instanceof Response) {
            // Make sure we validate chunks are BufferSources and convert them to
            // Uint8Arrays as required by the Rust glue code.
            response = new Response(response.body, response);
        }
        let rewriter;
        const readable = new ReadableStream({
            start: async (controller) => {
                // Create a rewriter instance for this transformation that writes its
                // output to the transformed response's stream. Note that each
                // BaseHTMLRewriter can only be used once.
                await HTMLRewriter.initPromise;
                // console.log('creating rewriter')
                rewriter = new RawHTMLRewriter((chunk) => {
                    // enqueue will throw on empty chunks
                    if (chunk.length !== 0)
                        controller.enqueue(chunk);
                }, { enableEsiTags: false });
                // Add all registered handlers
                for (const [selector, handlers] of this.elementHandlers) {
                    rewriter.on(selector, handlers);
                }
                for (const handlers of this.documentHandlers) {
                    rewriter.onDocument(handlers);
                }
                // Pipe the response body to the rewriter
                const reader = body.getReader();
                try {
                    while (true) {
                        // console.log('reading')
                        const { done, value } = await reader.read();
                        if (done)
                            break;
                        rewriter.write(value);
                    }
                    rewriter.end();
                }
                catch (error) {
                    // rewriter.end()
                    controller.error(error);
                }
                finally {
                    rewriter.free();
                    reader.releaseLock();
                    controller.close();
                }
            },
        });
        // Return a response with the transformed body, copying over headers, etc
        const res = new Response(readable, response);
        // If Content-Length is set, it's probably going to be wrong, since we're
        // rewriting content, so remove it
        res.headers.delete('Content-Length');
        return res;
    }
}
export function HTMLRewriterWrapper(initPromise) {
    HTMLRewriter.initPromise = initPromise;
    return HTMLRewriter;
}
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