Function parseSSE

src/ext/eventsource.js:13–75

(reader)

// ========================================

async function* parseSSE(reader) {
	var decoder = new TextDecoder();
	var buffer = '';
	var hasData = false;
	var message = { data: '', event: '', id: '', retry: null };
	var firstChunk = true;

	try {
		while (true) {
			var { done, value } = await reader.read();
			if (done) break;

			var chunk = decoder.decode(value, { stream: true });
			if (firstChunk) {
				if (chunk.charCodeAt(0) === 0xFEFF) chunk = chunk.slice(1);
				firstChunk = false;
			}
			buffer += chunk;

			var lines = buffer.split(/\r\n|\r|\n/);
			buffer = lines.pop() || '';

			for (var i = 0; i < lines.length; i++) {
				var line = lines[i];
				if (!line) {
					if (hasData) {
						yield message;
						hasData = false;
						message = { data: '', event: '', id: '', retry: null };
					}
					continue;
				}

				var colonIndex = line.indexOf(':');
				if (colonIndex === 0) continue;

				var field, val;
				if (colonIndex < 0) {
					field = line;
					val = '';
				} else {
					field = line.slice(0, colonIndex);
					val = line.slice(colonIndex + 1);
					if (val[0] === ' ') val = val.slice(1);
				}

				if (field === 'data') {
					message.data += (hasData ? '\n' : '') + val;
					hasData = true;
				} else if (field === 'event') {
					message.event = val;
				} else if (field === 'id') {
					if (!val.includes('\0')) message.id = val;
				} else if (field === 'retry') {
					var retryValue = parseInt(val, 10);
					if (!isNaN(retryValue)) message.retry = retryValue;
				}
			}