fetch-retry-ts
v1.3.1
Published
Adds retry functionality to fetch()
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fetch-retry-ts
Adds retry functionality to fetch()
.
Installation
npm install fetch-retry-ts
Usage
import originalFetch from 'isomorphic-fetch';
import fetchBuilder from 'fetch-retry-ts';
const options = {
retries: 3,
retryDelay: 1000,
retryOn: [419, 503, 504],
};
const fetch = fetchBuilder(originalFetch, options);
fetch('https://example.com/').then(/* ... */);
fetch-retry-ts
exports a function, which is used to build the new fetch()
-compatible function supporting the retry logic.
It accepts two arguments:
fetch
(required): the originalfetch()
function (fromisomorphic-fetch
etc)defaults
(optional): default values for the retry logic:retries?: number
: number of attempts to make (3 by default);retryDelay?: number | () => number | (attempt: number, error: Error | null, response: Response | null) => number
: delay between attempts (in ms). If specified as a function, the function accepts the following parameters:attempt
: the number of the current attempt;error
:Error
object coming fromfetch()
when it rejects on a network failure, ornull
;response
:Response
ornull
iferror !== null
It should return an integer, which is treated as the delay in ms before the enxt attempt is made. The default value forretryDelay
is1000
.
retryOn?: number[] | (attempt: number, retries: number, error: Error | null, response: Response | null) => boolean
: if specified as an array of integers, it is treated as a list of HTTP codes which trigger retry. When specified as a function, that functoin accepts the same parameters as the one described inretryDelay
, and an additional parameter calledretries
, whcih is the number of configured retries. The function should return a truthy value if the request should be retried. IfretryOn
is a function,retries
is ignored. The default value forretryOn
in[429, 503, 504]
. It returns a function to be used instead offetch()
.
The returned function accepts the same arguments as fetch(input: RequestInfo, init?: RequestInit)
, and three additional properties in init
object. Those are retries
, retryDelay
, and retryOn
.
Examples
Retry on any 5xx Error
fetch(url, {
retryOn: (attempt: number, retries: number, error: Error | null, response: Response | null): boolean => (
attempt < retries && (!!error || !response || response.status >= 500)
),
}).then(/* ... */)
Retry only on Network Failures
fetch(url, {
retryOn: [],
}).then(/* ... */)
Do not retry on Network Failures
fetch(url, {
retryOn: (attempt: number, retries: number, error: Error | null, response: Response | null): boolean => (
attempt < retries && error === null /* && additional logic to check response code */
),
}).then(/* ... */)
Exponential Backoff
fetch(url, {
retryDelay: (attempt: number, error: Error | null, response: Response | null): number => (
Math.pow(2, attempt) * 1000
),
}).then(/* ... */)