avait

Async error handling without try-catch.

Usage

import { it } from 'avait'
import { readFile } from 'fs/promises'

const { error, value } = await it(readFile('./my-file.txt', 'utf-8'))

if (error) return alert('Error')
console.log(`File contents: ${value}`)

It's possible to resolve multiple promises in a row.

const { error, title } = await it(fetch('https://dummyjson.com/products/1')).add((next) =>
  next.json(),
)
// title => 'iPhone 9'

Error Handler

When an error is thrown but the error property isn't accessed errors will be sent to any registered error handlers.

import { it, registerErrorHandler } from 'avait'
import { readFile } from 'fs/promises'

registerErrorHandler((error) => alert(error))

const { value } = await it(readFile('./my-file.txt', 'utf-8'))

console.log(`File contents: ${value}`)

Multiple Promises

It's possible to pass an array of promises. In this case the result value as well as the error will also be returned as an array. Using the second argument parallelism can be enabled which leads to the promises being run in parallel.

import { it } from 'avait'

const { value } = await it([firstPromise, secondPromise])
console.log(value[0])
// With parallelism enabled
const { value } = await it([firstPromise, secondPromise], { parallel: true })
console.log(value[1])

Converting an Async Method to a Synchronous One

Using the toSync method it's possible to leverage node worker_threads to turn an async method into a synchronous one. This is usually not necessary nor recommended as asynchronous methods are supported in any environment nowadays. As the first argument the method accepts a module path or a file (basically anything that can be passed to import) with a specific export as the second argument which will default to the default export. The second argument can be an array in case multiple calls should be chained. Proper chaining is important as the final result needs to be serializable in order to be passed back from the worker. The function returned by toSync can then be synchronously be called adding any arguments as an array or in the case of chaining multiple arrays.

import { toSync } from 'avait/synchronize'

// Synchronize an async module.
const fileContents = toSync('fs/promises', 'readFile')('./my-file.txt', 'utf-8')
const { title } = toSync('node-fetch', ['default', 'json'])([
  ['https://dummyjson.com/products/1'],
  [],
])
const { id, description } = toSync('axios', ['get', 'data'])([['https://dummyjson.com/products/1']])

// Synchronize an async method from a local file.
const prased = toSync('../parse-data.js', 'parse')([[data]])

Credits

Error handling inspired by await-to-js.

Async to sync approach taken from @prettier/sync.