try-n-catch v2.0.1

try-n-catch

Functional try-catch wrapper. TypeScript typings included.
Provides a different way to handle errors.

Example

import tryCatch from 'try-n-catch'

const string = prompt('Enter a JSON object')
const [value, error] = tryCatch(JSON.parse, string)

if (error) {
  // `value` is undefined, `error` is the error thrown by JSON.parse()
  alert('This is not a valid JSON object.')
  console.log(error)
} else {
  // `value` is the parsed object, `error` is undefined
  console.log(value)
}

// Note how both `value` and `error` are immutable and visible in the outer scope.

More examples

Using an arrow function

Use an arrow function if you prefer to.

tryCatch(JSON.parse, string)
tryCatch(() => JSON.parse(string))

Async function error handling

Use tryCatch.async() to handle errors in async functions. tryCatch.sync() is the same as tryCatch().

const [response, error] = await tryCatch.async(fetch, 'https://google.com')

If you wish, you can import trySync() and tryAsync(), which act the same as tryCatch() and tryCatch.async() respectively.

import { trySync, tryAsync } from 'try-n-catch'

Check if a function threw

If a function may throw undefined, it won't be possible to handle the error using if (err) construct, use if (threw) to instead.

const [value, error, threw] = tryCatch(() => {
  throw undefined
})

// both value and error are undefined, but threw is true

if (threw) {
  // handle the error
}

Named properties

value, error and threw properties are available on the returned array. It could be useful in a scenario where you only need to check if a function throws.

if (tryCatch(someFunction).threw) {
  // the function threw
}

Precaution

Don't use this in large loops where performance is important.
Don't use this in functions that could be called in large loops where performance is important.