Interface: ClientOptions<SingleConnection>

client.ClientOptions

Type parameters

Name	Type
`SingleConnection`	extends `boolean` = `false`

Properties

abortControllerImpl

• Optional abortControllerImpl: unknown

The AbortController implementation to use.

For NodeJS environments before v15 consider using node-abort-controller.

Default

global.AbortController

Defined in

src/client.ts:181

credentials

• Optional credentials: "omit" | "same-origin" | "include"

Indicates whether the user agent should send cookies from the other domain in the case of cross-origin requests.

Possible options are:

omit: Never send or receive cookies.
same-origin: Send user credentials (cookies, basic http auth, etc..) if the URL is on the same origin as the calling script.
include: Always send user credentials (cookies, basic http auth, etc..), even for cross-origin calls.

Default

same-origin

Defined in

src/client.ts:121

fetchFn

• Optional fetchFn: unknown

The Fetch function to use.

For NodeJS environments consider using node-fetch.

Default

global.fetch

Defined in

src/client.ts:173

generateID

• Optional generateID: () => string

A custom ID generator for identifying subscriptions.

The default generates a v4 UUID to be used as the ID using Math as the random number generator. Supply your own generator in case you need more uniqueness.

Reference: https://gist.github.com/jed/982883

Type declaration

▸ (): string

A custom ID generator for identifying subscriptions.

The default generates a v4 UUID to be used as the ID using Math as the random number generator. Supply your own generator in case you need more uniqueness.

Reference: https://gist.github.com/jed/982883

Returns

string

Defined in

src/client.ts:191

headers

• Optional headers: Record<string, string> | () => Record<string, string> | Promise<Record<string, string>>

HTTP headers to pass along the request.

If the option is a function, it will be called on each connection attempt. Returning a Promise is supported too and the connection phase will stall until it resolves with the headers.

A good use-case for having a function is when using the headers for authentication, where subsequent reconnects (due to auth) may have a refreshed identity token in the header.

Defined in

src/client.ts:163

lazy

• Optional lazy: SingleConnection extends true ? boolean : never

Controls when should the connection be established while using the client in “single connection mode” (see singleConnection option).

false: Establish a connection immediately.
true: Establish a connection on first subscribe and close on last unsubscribe.

Note that the lazy option has NO EFFECT when using the client in “distinct connections mode” (singleConnection = false).

Default

true

Defined in

src/client.ts:71

lazyCloseTimeout

• Optional lazyCloseTimeout: SingleConnection extends true ? number : never

How long should the client wait before closing the connection after the last operation has completed. You might want to have a calmdown time before actually closing the connection.

Meant to be used in combination with lazy.

Note that the lazy option has NO EFFECT when using the client in “distinct connections mode” (singleConnection = false).

Default

Defined in

src/client.ts:83

on

• Optional on: EventListeners<SingleConnection>

Event listeners for events happening in the SSE connection.

Will emit events for both the “single connection mode” and the default “distinct connections mode”.

Beware that the connecting event will be called for each subscription when using with “distinct connections mode”.

Defined in

src/client.ts:224

onMessage

• Optional onMessage: (message: StreamMessage<SingleConnection, StreamEvent>) => void

Browsers show stream messages in the DevTools only if they’re received through the native EventSource, and because graphql-sse implements a custom SSE parser - received messages will not appear in browser’s DevTools.

Use this function if you want to inspect valid messages received through the active SSE connection.

Deprecated

Consider using ClientOptions.on instead.

Type declaration

▸ (message): void

Use this function if you want to inspect valid messages received through the active SSE connection.

Parameters

Name	Type
`message`	`StreamMessage`<`SingleConnection`, `StreamEvent`>

Returns

void

Deprecated

Consider using ClientOptions.on instead.

Defined in

src/client.ts:216

onNonLazyError

• Optional onNonLazyError: SingleConnection extends true ? (error: unknown) => void : never

Used ONLY when the client is in non-lazy mode (lazy = false). When using this mode, errors might have no sinks to report to; however, to avoid swallowing errors, onNonLazyError will be called when either:

An unrecoverable error/close event occurs
Silent retry attempts have been exceeded

After a client has errored out, it will NOT perform any automatic actions.

Default

console.error

Defined in

src/client.ts:95

referrer

• Optional referrer: string

A string specifying the referrer of the request. This can be a same-origin URL, about:client, or an empty string.

Default

undefined

Defined in

src/client.ts:127

referrerPolicy

Specifies the referrer policy to use for the request.

Possible options are:

no-referrer: Does not send referrer information along with requests to any origin.
no-referrer-when-downgrade: Sends full referrerURL for requests: whose referrerURL and current URL are both potentially trustworthy URLs, or whose referrerURL is a non-potentially trustworthy URL.
same-origin: Sends full referrerURL as referrer information when making same-origin-referrer requests.
origin: Sends only the ASCII serialization of the request’s referrerURL when making both same-origin-referrer requests and cross-origin-referrer requests.
strict-origin: Sends the ASCII serialization of the origin of the referrerURL for requests: whose referrerURL and current URL are both potentially trustworthy URLs, or whose referrerURL is a non-potentially trustworthy URL
origin-when-cross-origin: Sends full referrerURL when making same-origin-referrer requests, and only the ASCII serialization of the origin of the request’s referrerURL is sent when making cross-origin-referrer requests
strict-origin-when-cross-origin: Sends full referrerURL when making same-origin-referrer requests, and only the ASCII serialization of the origin of the request’s referrerURL when making cross-origin-referrer requests: whose referrerURL and current URL are both potentially trustworthy URLs, or whose referrerURL is a non-potentially trustworthy URL.
unsafe-url: Sends full referrerURL along for both same-origin-referrer requests and cross-origin-referrer requests.

Default

undefined

Defined in

src/client.ts:143

retry

• Optional retry: (retries: number) => Promise<void>

Control the wait time between retries. You may implement your own strategy by timing the resolution of the returned promise with the retries count.

retries argument counts actual reconnection attempts, so it will begin with 0 after the first retryable disconnect.

Default

'Randomised exponential backoff, 5 times'

Type declaration

▸ (retries): Promise<void>

Control the wait time between retries. You may implement your own strategy by timing the resolution of the returned promise with the retries count.

retries argument counts actual reconnection attempts, so it will begin with 0 after the first retryable disconnect.

Parameters

Name	Type
`retries`	`number`

Returns

Promise<void>

Default

'Randomised exponential backoff, 5 times'

Defined in

src/client.ts:207

retryAttempts

• Optional retryAttempts: number

How many times should the client try to reconnect before it errors out?

Default

Defined in

src/client.ts:197

singleConnection

• Optional singleConnection: SingleConnection

Reuses a single SSE connection for all GraphQL operations.

When instantiating with false (default), the client will run in a “distinct connections mode” mode. Meaning, a new SSE connection will be established on each subscribe.

On the other hand, when instantiating with true, the client will run in a “single connection mode” mode. Meaning, a single SSE connection will be used to transmit all operation results while separate HTTP requests will be issued to dictate the behaviour.

Default

false

Defined in

src/client.ts:58

url

• url: string | () => string | Promise<string>

URL of the GraphQL over SSE server to connect.

If the option is a function, it will be called on each connection attempt. Returning a Promise is supported too and the connection phase will stall until it resolves with the URL.

A good use-case for having a function is when using the URL for authentication, where subsequent reconnects (due to auth) may have a refreshed identity token in the URL.

Defined in

src/client.ts:109

client.Client client.EventListeners