Fix livereload injection; monkeypatching `write` no longer works in newer Node versions

operations/development-server.js

@@ -5,35 +5,57 @@ const defaultValue = require("default-value");
 const assureArray = require("assure-array");
 const path = require("path");
 const entities = require("entities");
+const util = require("util");
 
-let reloadClientTag = "<script src=\"/budo/livereload.js\"></script>";
+let reloadClientTag = Buffer.from("<script src=\"/budo/livereload.js\"></script>");
 
-function monkeyPatchWrite(res) {
+function monkeyPatchEnd(res) {
 	// NOTE: This is a hack, to auto-inject the Budo livereload client in any outgoing HTML response (but only in development mode).
-	let write = res.write.bind(res);
+	let end = res.end.bind(res);
 
-	res.write = function monkeyPatchedWrite(... args) {
-		if (res.getHeader("content-type").startsWith("text/html")) {
-			let contentLength = res.getHeader("content-length");
-			
-			if (contentLength != null) {
-				// Compensate for the additional bytes introduced by our injected script tag
-				res.setHeader("content-length", contentLength + reloadClientTag.length);
+	res.end = function monkeyPatchedEnd(... args) {
+		let originalChunk = args[0];
+		let prefix;
+
+		if (originalChunk == null || Buffer.isBuffer(originalChunk)) {
+			if (res.getHeader("content-type").startsWith("text/html")) {
+				let contentLength = res.getHeader("content-length");
+				
+				if (contentLength != null) {
+					// Compensate for the additional bytes introduced by our injected script tag
+					res.setHeader("content-length", parseInt(contentLength) + reloadClientTag.length);
+				}
+	
+				prefix = reloadClientTag;
 			}
 			
-			write(reloadClientTag);
-		}
-		
-		// Reset the write method back to the original method; we don't need to get in the way anymore
-		res.write = write;
+			// Reset the `end` method back to the original method; we don't need to get in the way anymore
+			res.end = end;
+	
+			if (prefix != null) {
+				let chunk = (originalChunk == null)
+					? reloadClientTag
+					: Buffer.concat([ originalChunk, reloadClientTag ]);
 
-		write(... args);
+				end(chunk, ... args.slice(1));
+			} else {
+				end(... args);
+			}
+		} else {
+			throw new Error(`Expected a buffer in 'end', but got something else: ${util.inspect(args[0])}`);
+		}
 	};
 }
 
 function createExpressMiddleware(app) {
 	return function expressMiddleware(req, res, next) {
-		monkeyPatchWrite(res);
+		try {
+			monkeyPatchEnd(res);
+		} catch (error) {
+			process.nextTick(() => {
+				throw error;
+			});
+		}
 
 		app.handle(req, res, (err) => {
 			if (err != null && err instanceof Error) {