tryloop
v2.0.2
Published
Simple library for retrying operations, it supports multiple backoff strategies.
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TryLoop
Simple library for retrying operations, it supports multiple backoff strategies.
Install
npm install --save tryloop
Usage
You'll have to provide the options.fn
function, which will be the operation to retry.
- If the function throws, TryLoop will throw.
- If the function returns
undefined
, or aPromise
which resolves toundefined
, the operation will be retried. - If the function returns any other value, or a
Promise
which resolves to any other value, TryLoop will return aPromise
to that value. - If the function can't be retried any longer, e.g. maybe the timeout run out or we hit the max retries limit, TryLoop will return
undefined
.
There are multiple backoff/retry strategies implemented, each with its own particular retry logic.
In general you're going to use the library like this:
import tryloop from 'tryloop';
const instance = tryloop.__strategy_name__ ({
fn: () => {}, // Operation to retry
// Other options...
});
const result = await instance.start ();
// instance.stop (); // Stops retrying the operation
// instance.cancel (); // Just an alias for "stop"
Strategies
Linear
The linear strategy retries the operation after a fixed interval.
These are the accepted options:
type Options = {
fn: () => any, // Operation to retry
timeout: number, // Return undefined after this timeout
tries: number, // Return undefined after this number of tries
interval: number // Fixed interval between retries
};
You can use it like so:
import tryloop from 'tryloop';
const instance = tryloop.linear ({
fn: () => {}, // Operation to retry
timeout: 10000, // Time out after 10s
tries: 100, // Not more than 100 tries
interval: 100 // Wait 100ms between retries
});
const value = await instance.start ();
Idle
The idle strategy retries the operation by calling requestIdleCallback
.
These are the accepted options:
type Options = {
fn: () => any, // Operation to retry
timeout: number, // Return undefined after this timeout
tries: number // Return undefined after this number of tries
};
You can use it like so:
import tryloop from 'tryloop';
const instance = tryloop.idle ({
fn: () => {}, // Operation to retry
timeout: 10000, // Time out after 10s
tries: 100 // Not more than 100 tries
});
const value = await instance.start ();
Exponential
The exponential strategy retries the operation with exponentially increasing intervals.
These are the accepted options:
type Options = {
fn: () => any, // Operation to retry
timeout: number, // Return undefined after this timeout
tries: number, // Return undefined after this number of tries
factor: number, // Base factor which will be exponentiated after each try
minInterval: number, // Minimum interval between retries, also starting interval
maxInterval: number // Maximum interval between retries
};
You can use it like so:
import tryloop from 'tryloop';
const instance = tryloop.exponential ({
fn: () => {}, // Operation to retry
timeout: 10000, // Time out after 10s
tries: 100, // Not more than 100 tries
factor: 2, // Base factor
minInterval: 1, // Start with 1ms
maxInterval: 1000 // No more than 1s between retries
});
const value = await instance.start ();
requestAnimationFrame
The idle strategy retries the operation by calling requestAnimationFrame
.
These are the accepted options:
type Options = {
fn: () => any, // Operation to retry
timeout: number, // Return undefined after this timeout
tries: number // Return undefined after this number of tries
};
You can use it like so:
import tryloop from 'tryloop';
const instance = tryloop.raf ({
fn: () => {}, // Operation to retry
timeout: 10000, // Time out after 10s
tries: 100 // Not more than 100 tries
});
const value = await instance.start ();
License
MIT © Fabio Spampinato