Fuels-ts

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Provider Options ​

You can provide various options on Provider instantiation to modify its behavior.

retryOptions ​

Calls to a fuel node via the Provider will fail if a connection cannot be established. Specifying retry options allows you to customize the way you want to handle that failure scenario before ultimately throwing an error.

NOTE: retrying is only done when a connection cannot be established. If the connection is established and the node throws an error, no retry will happen.

You can provide the following settings:

  • maxRetries - Amount of attempts to retry after initial attempt before failing the call.
  • backoff - Strategy used to define the intervals between attempts.
    • exponential (default): Doubles the delay with each attempt.
    • linear - Increases the delay linearly with each attempt.
    • fixed: Uses a constant delay between attempts.
  • baseDelay (default 150ms) - Base time in milliseconds for the backoff strategy.
ts
await Provider.create(FUEL_NETWORK_URL, {
  retryOptions: {
    maxRetries: 5,
    baseDelay: 100,
    backoff: 'linear',
  },
});
See code in context

requestMiddleware ​

Allows you to modify the request object to add additional headers, modify the request's body, and much more.

ts
// synchronous request middleware
await Provider.create(FUEL_NETWORK_URL, {
  requestMiddleware: (request: RequestInit) => {
    request.credentials = 'omit';

    return request;
  },
});

// asynchronous request middleware
await Provider.create(FUEL_NETWORK_URL, {
  requestMiddleware: async (request: RequestInit) => {
    const credentials = await fetchSomeExternalCredentials();
    request.headers ??= {};
    (request.headers as Record<string, string>).auth = credentials;

    return request;
  },
});
See code in context

timeout ​

Specify the timeout in milliseconds after which every request will be aborted.

ts
await Provider.create(FUEL_NETWORK_URL, {
  timeout: 30000, // will abort if request takes 30 seconds to complete
});
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fetch ​

Provide a custom fetch function that'll replace the default fetch call.

Note: If defined, requestMiddleware, timeout and retryOptions are applied to this custom fetch function as well.

ts
await Provider.create(FUEL_NETWORK_URL, {
  fetch: async (url: string, requestInit: RequestInit | undefined) => {
    // do something
    await sleep(100);

    // native fetch
    const response = await fetch(url, requestInit);

    const updatedResponse = decorateResponseWithCustomLogic(response);

    return updatedResponse;
  },
});
See code in context