Checkpoint

> Tired of always failing in life? Well, we cannot help with that. But we can help you fail less in a node application.

[![npm package][npm-img]][npm-url]
[![Downloads][downloads-img]][downloads-url]
[![Code Coverage][codecov-img]][codecov-url]

checkpoint is the ultimate flaky code helper. With modern days applications, where we must integrate with external services, which can fail. We have to figure out a way of retrying our code. We must go back to somewhere we know we where fine. We must return to a checkpoint.

Install

``bash
npm install @fintoc/checkpoint
`

Usage

`ts
import { checkpoint, retry } from '@fintoc/checkpoint';

// we define how many retries we can make
await checkpoint({ retries: 3 }, () => {
// do some awesome stuff
// ...
// ...

// this is weird, this number should not be bigger than the other
if (someNumber < otherNumber) retry();

try {
// solving SAT in polynomial time
} catch (error) {
// this error is a flaky one, we should just retry
retry();
}
});
`

$3

At one point or another, we might want to set different checkpoints, and to go back to which ever checkpoint we want. We can do this by specifying a name for a specific checkpoint.

`ts
await checkpoint({ name: 'first' }, async () => {
// doing really important stuff
// ...

await checkpoint({ name: 'second' }, () => {

if (somethingHappends) {
// something went horrible, we must go even further back
retry('first');
}
});
});
`

$3


We might have to perfom some operations in order to come back to a useful state in order to retry our code. We can set this by using the onRetry callback option.

`ts
function onRetry() {
a = 0;
}
await checkpoint({ onRetry }, () => {

// a changes its value

if (someThingHappends) {
retry(); // a will start at 0 at the next try
}
});
`

$3

The checkpoint options are as followed:

`ts
{
name: 'checkpointId', // checkpoint name to reference in retries, defaults to null
logger: console.log, // function to log the checkpoint execution, defaults to null
retries: 3, // how many retries are available before raising an error, defaults to 1
onRetry: () => { // specify a callback before retrying
// do things
},
onFailure: () => { // specify a callback when retry limit is reached
// raise custom error or whatever you want
},
}
`

$3


Additionally, the checkpoint function returns the value of the callback function passed as its parameter (if the function reaches a return value before any retry or exception). In the case in which the checkpoint reaches the retry limit, then the checkpoint returns the value of the onFailure function

`ts
function onFailure() {
return 'failed'
}

// returnValue might endup being 'failed' or 'success'
const returnValue = await checkpoint({ onFailure }, () => {
...
// it may retry at some point
...
return 'success'
});
``

[downloads-img]:https://img.shields.io/npm/dt/@fintoc/checkpoint
[downloads-url]:https://www.npmtrends.com/@fintoc/checkpoint
[npm-img]:https://img.shields.io/npm/v/@fintoc/checkpoint
[npm-url]:https://www.npmjs.com/package/@fintoc/checkpoint
[codecov-img]:https://codecov.io/gh/ryansonshine/typescript-npm-package-template/branch/main/graph/badge.svg
[codecov-url]:https://codecov.io/gh/ryansonshine/typescript-npm-package-template