astoilkov / good-try

Tries to execute a sync/async function, returns a specified default value if the function throws

good-try

Tries to execute a sync/async function, returns a specified default value if the function throws.

Why

Why not nice-try with it's 70+ million downloads per month?

• good-try supports async functions.
• good-try supports an optional default value.
• good-try allows you to capture the thrown error.
• good-try is written in TypeScript. The types are written in a way that reduce developer errors. For example, I sometimes incorrectly type goodTry(readFileSync()), but the types don't allow this.
• good-try has a friend — settle-it.
• I aim for high-quality with my open-source principles.

Why not just try/catch?

• In a lot of cases, try/catch is still the better option.
• Nested try/catch statements are hard to process mentally. They also indent the code and make it hard to read. A single try/catch does the same but to a lesser degree.
• If you prefer const, try/catch statements get in the way because you need to use let if you need the variable outside of the try/catch scope:

  let todos;
  try {
      todos = JSON.parse(localStorage.getItem('todos'))
  } catch {}
  return todos.filter(todo => todo.done)

• It takes more space. It's slower to type.

Install

npm install good-try

Usage

import goodTry from 'good-try'

// tries to parse todos, returns empty array if it fails
const value = goodTry(() => JSON.parse(todos), [])

// fetch todos, on error, fallback to empty array
const todos = await goodTry(fetchTodos(), [])

// fetch todos, fallback to empty array, send error to your error tracking service
const todos = await goodTry(fetchTodos(), (err) => {
    sentToErrorTrackingService(err)
    return []  
})

API

First parameter accepts:

• synchronous function goodTry(() => JSON.parse(value))
• asynchronous function / Promise
• synchronous function that returns a promise

Second parameter accepts:

• any value that will be returned if the first parameter throws
• a callback that receives err as first parameter (the return value of the callback is returned if the first parameter throws)

If you use TypeScript, the types are well defined and won't let you make a mistake.

Related

• settle-it – Like Promise.allSettled() but for sync and async functions. Similarly to good-try it handles sync/async functions that throw an error. However, it returns an object so you know if and what error was thrown.