Expose ShellError

[ajitid]

What is the problem this feature would solve?

Right now when I install @types/bun and write:

import { $, ShellError } from 'bun'

try {
  await $`a-command-that-will-surely-fail`
} catch (err) {
  if (err instanceof ShellError) {
    // handle error
  }
}

The code doesn't give TypeScript error but fails at runtime because ShellError is undefined.

What is the feature you are proposing to solve the problem?

Expose ShellError class, just like $ is available. This way I would be able to use instanceof on it.

What alternatives have you considered?

I tried two workarounds neither which I liked:

1. Intentionally make Bun shell throw error once so I could grab an actual instance

import { $, type ShellError } from 'bun'

let classCtor: Function
try {
  await $`a-command-that-will-surely-fail^#^#`
} catch (err: any) {
  classCtor = err.constructor
}

export const isShellError = (err: any): err is ShellError => {
  return err instanceof classCtor
}

2. Check if properties match, and declare the error as ShellError

import { type ShellError } from 'bun'

export const isShellError = (err: any): err is ShellError => {
  if (err === null) return false
  if (typeof err !== 'object') return false
  return (
    err.constructor?.name === 'ShellError' &&
    typeof err.json === 'function' &&
    typeof err.exitCode === 'number'
  )
}

[alii]

This is fixed in #17424. Working on fixing other type declaration issues before that merges