JavaScript error handling with better `dx`

Jason Tu — Wed, 07 Nov 2018 08:23:04 +0000

JavaScript expects you to handle errors with try...catch, but the syntax is somewhat inconvenient:

1. You have to declare result variables separately from your function calls.

const userInput = 'fail'

let json
try {
  json = JSON.parse(userInput)
} catch (err) {
  console.error(err.stack)
}

// Do something with `json`...

Since we declare json separately, we can't declare json as a const binding.

2. `try...catch` promotes catch-all error handling.

try {
  // A bunch of stuff happens...
  // ...
  // ...
} catch (err) {
  console.log('welp')
  console.error(err.stack)
}

You might want to handle errors in a more fine-grained way. But then you run into the verbosity of problem 1.

Enter `dx`

dx is a micro utility (it's just a few lines) that addresses the two pain points above.

import { dx } from '@nucleartide/dx'

const [res, err] = dx(JSON.parse)('invalid json')
if (err) {
  console.error(err.stack)
}

It allows you to place your declaration and function call on the same line. And it promotes a granular, per-function error handling style.

It also works with async functions:

import { dx } from '@nucleartide/dx'

function asyncHello(name) {
  return Promise.reject(`hello ${name}`)
}

;(async () => {
  const [res, err] = await dx(asyncHello)('jesse')
  if (err) {
    console.error(err.stack)
  }
})

Convinced?

Try it out and lemme know what you think! Also feel free to check out the source.

npm install @nucleartide/dx

Forem: Jason Tu

JavaScript error handling with better `dx`

1. You have to declare result variables separately from your function calls.

2. try...catch promotes catch-all error handling.

Enter dx

Convinced?

2. `try...catch` promotes catch-all error handling.

Enter `dx`