You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
149 lines
3.5 KiB
149 lines
3.5 KiB
# p-retry
|
|
|
|
> Retry a promise-returning or async function
|
|
|
|
It does exponential backoff and supports custom retry strategies for failed operations.
|
|
|
|
## Install
|
|
|
|
```
|
|
$ npm install p-retry
|
|
```
|
|
|
|
## Usage
|
|
|
|
```js
|
|
const pRetry = require('p-retry');
|
|
const fetch = require('node-fetch');
|
|
|
|
const run = async () => {
|
|
const response = await fetch('https://sindresorhus.com/unicorn');
|
|
|
|
// Abort retrying if the resource doesn't exist
|
|
if (response.status === 404) {
|
|
throw new pRetry.AbortError(response.statusText);
|
|
}
|
|
|
|
return response.blob();
|
|
};
|
|
|
|
(async () => {
|
|
console.log(await pRetry(run, {retries: 5}));
|
|
})();
|
|
```
|
|
|
|
## API
|
|
|
|
### pRetry(input, options?)
|
|
|
|
Returns a `Promise` that is fulfilled when calling `input` returns a fulfilled promise. If calling `input` returns a rejected promise, `input` is called again until the maximum number of retries is reached. It then rejects with the last rejection reason.
|
|
|
|
|
|
Does not retry on most `TypeErrors`, with the exception of network errors. This is done on a best case basis as different browsers have different [messages](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch#Checking_that_the_fetch_was_successful) to indicate this. See [whatwg/fetch#526 (comment)](https://github.com/whatwg/fetch/issues/526#issuecomment-554604080)
|
|
|
|
|
|
#### input
|
|
|
|
Type: `Function`
|
|
|
|
Receives the current attempt number as the first argument and is expected to return a `Promise` or any value.
|
|
|
|
#### options
|
|
|
|
Type: `object`
|
|
|
|
Options are passed to the [`retry`](https://github.com/tim-kos/node-retry#retryoperationoptions) module.
|
|
|
|
##### onFailedAttempt(error)
|
|
|
|
Type: `Function`
|
|
|
|
Callback invoked on each retry. Receives the error thrown by `input` as the first argument with properties `attemptNumber` and `retriesLeft` which indicate the current attempt number and the number of attempts left, respectively.
|
|
|
|
```js
|
|
const run = async () => {
|
|
const response = await fetch('https://sindresorhus.com/unicorn');
|
|
|
|
if (!response.ok) {
|
|
throw new Error(response.statusText);
|
|
}
|
|
|
|
return response.json();
|
|
};
|
|
|
|
(async () => {
|
|
const result = await pRetry(run, {
|
|
onFailedAttempt: error => {
|
|
console.log(`Attempt ${error.attemptNumber} failed. There are ${error.retriesLeft} retries left.`);
|
|
// 1st request => Attempt 1 failed. There are 4 retries left.
|
|
// 2nd request => Attempt 2 failed. There are 3 retries left.
|
|
// …
|
|
},
|
|
retries: 5
|
|
});
|
|
|
|
console.log(result);
|
|
})();
|
|
```
|
|
|
|
The `onFailedAttempt` function can return a promise. For example, you can do some async logging:
|
|
|
|
```js
|
|
const pRetry = require('p-retry');
|
|
const logger = require('./some-logger');
|
|
|
|
const run = async () => { … };
|
|
|
|
(async () => {
|
|
const result = await pRetry(run, {
|
|
onFailedAttempt: async error => {
|
|
await logger.log(error);
|
|
}
|
|
});
|
|
})();
|
|
```
|
|
|
|
If the `onFailedAttempt` function throws, all retries will be aborted and the original promise will reject with the thrown error.
|
|
|
|
### pRetry.AbortError(message)
|
|
### pRetry.AbortError(error)
|
|
|
|
Abort retrying and reject the promise.
|
|
|
|
### message
|
|
|
|
Type: `string`
|
|
|
|
Error message.
|
|
|
|
### error
|
|
|
|
Type: `Error`
|
|
|
|
Custom error.
|
|
|
|
## Tip
|
|
|
|
You can pass arguments to the function being retried by wrapping it in an inline arrow function:
|
|
|
|
```js
|
|
const pRetry = require('p-retry');
|
|
|
|
const run = async emoji => {
|
|
// …
|
|
};
|
|
|
|
(async () => {
|
|
// Without arguments
|
|
await pRetry(run, {retries: 5});
|
|
|
|
// With arguments
|
|
await pRetry(() => run('🦄'), {retries: 5});
|
|
})();
|
|
```
|
|
|
|
## Related
|
|
|
|
- [p-timeout](https://github.com/sindresorhus/p-timeout) - Timeout a promise after a specified amount of time
|
|
- [More…](https://github.com/sindresorhus/promise-fun)
|