damianstasik / catcher

@isaacs/catcher

Call a function and return a fallback value or undefined if it throws.

Cuts out the performance overhead of creating a stack trace, for cases where it won't be used anyway.

USAGE

import { catcher, catchWrap } from '@isaacs/cached'
import { functionThatMightThrow } from 'some-module'

const resultOrUndefined = catcher(functionThatMightThrow)
const resultOr99 = catcher(functionThatMightThrow, 99)

const functionThatDoesNotThrow = catchWrap(functionThatMightThrow)
// this returns undefined rather than throwing
const resultOrUndefined = functionThatDoesNotThrow(123)

const return99onFailure = catchWrap(functionThatMightThrow, 99)
const resultOr99 = return99onFailure(234)

Properly supports types for the returned function if the function being wrapped has up to 10 overload signatures, but the parameters and return types are each squashed into a single tuple. For example:

function x(): boolean
function x(s: string): string
function x(s?: string) {
  if (typeof s === 'undefined') return true
  else if (typeof s === 'string') return s
  else throw new Error('not a string or undefined')
}

const wrapped = catchWrap(x, 99)
// wrapped is now (...a: [] | [string]) => boolean | string | 99

See the typedocs for detailed API info.