HTTP — fetch / Request / Response / SSE

Web-standard Fetch API and Server-Sent Events.

fetch

const response = await fetch("https://api.example.com/data");
const json = await response.json();

// POST
const response = await fetch("https://api.example.com/submit", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({ name: "rong" }),
});

Signature

fetch(input: string | Request | URL, init?: RequestInit): Promise<Response>

RequestInit

Property	Type	Description
method	string	HTTP method, default "GET"
headers	Headers | Record<string, string> | [string, string][]	Request headers
body	string | ArrayBuffer | Uint8Array | Blob | FormData | URLSearchParams | ReadableStream	Request body
redirect	"follow" | "error" | "manual"	Redirect policy
signal	AbortSignal	Cancellation signal

---

Request

const req = new Request("https://api.example.com", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({ key: "value" }),
});

const req2 = new Request(req); // clone from existing

Properties

Property	Type	Description
url	string	Request URL
method	string	HTTP method
headers	Headers	Request headers
body	ReadableStream | null	Body stream
redirect	string	Redirect policy
signal	AbortSignal	Cancellation signal

Methods

Method	Returns	Description
clone()	Request	Clone the request
text()	Promise<string>	Read body as text
json()	Promise<any>	Read body as JSON
arrayBuffer()	Promise<ArrayBuffer>	Read body as binary
blob()	Promise<Blob>	Read body as Blob

---

Response

// Manual construction
const res = new Response("Hello", {
  status: 200,
  headers: { "Content-Type": "text/plain" },
});

// From fetch
const res = await fetch(url);
if (res.ok) {
  const data = await res.json();
}

Properties

Property	Type	Description
url	string	Response URL
status	number	HTTP status code
statusText	string	Status text
ok	boolean	Status 200-299
headers	Headers	Response headers
body	ReadableStream | null	Body stream
bodyUsed	boolean	Whether body is consumed
redirected	boolean	Whether redirected
type	string	Response type

Methods

Method	Returns
text()	Promise<string>
json()	Promise<any>
arrayBuffer()	Promise<ArrayBuffer>
blob()	Promise<Blob>
formData()	Promise<FormData>
clone()	Response

---

Headers

const h = new Headers({ "Content-Type": "application/json" });
const h2 = new Headers([["Accept", "text/html"], ["Accept", "application/json"]]);
const h3 = new Headers(existingHeaders);

h.set("Authorization", "Bearer token");
h.append("Accept", "text/html");
h.get("Content-Type"); // "application/json"
h.has("Authorization"); // true
h.delete("Authorization");

for (const [name, value] of h.entries()) {
  console.log(`${name}: ${value}`);
}

Method	Description
get(name)	Get value
set(name, value)	Set value
append(name, value)	Append value
delete(name)	Delete
has(name)	Check existence
getSetCookie()	Get all Set-Cookie header values (Rong extension)
entries()	Iterate [name, value]
keys()	Iterate names
values()	Iterate values
forEach(fn)	For each entry

---

SSE (Server-Sent Events)

const sse = new Rong.SSE("https://api.example.com/events", {
  headers: { Authorization: "Bearer token" },
  signal: AbortSignal.timeout(60000),
  reconnect: {
    enabled: true,
    baseDelayMs: 1000,
    maxDelayMs: 30000,
    maxRetries: 10,
  },
  requestTimeoutMs: 60000,
});

for await (const event of sse) {
  console.log(event.type, event.data);
  if (done) break; // triggers close + cleanup
}

// Manual close
sse.close();

Properties

Property	Type	Description
url	string	Connection URL

Methods

Method	Description
close()	Close connection

Options

Option	Type	Description
headers	Record<string, string>	Custom request headers
signal	AbortSignal	Cancellation signal
requestTimeoutMs	number	Request timeout in milliseconds
reconnect	object	Reconnect policy (enabled, maxRetries, baseDelayMs, maxDelayMs)

Yielded event shape

Property	Type
type	string
data	string
id	string
origin	string