balena-io-modules/typed-error

This module allows you to easily extend the built-in Error type for typed error checking

For typescript:

import { TypedError } from 'typed-error'

class MyError extends TypedError {}

try {
    throw new MyError()
} catch(e) {
    console.log(e instanceof MyError) // true
    console.log(e.name) // 'MyError'
    console.log(e.constructor.name) // 'MyError'
    console.log(e.stack) // <stack trace>

    if(e instanceof MyError) {
        console.log('Do custom handling')
    } else {
        console.log('Another type of error')
    }

    // Or
    switch(e.name) {
        case 'MyError':
            console.log('Do custom handling')
        break;
        default:
            console.log('Another type of error')
    }

    // Or
    switch(e.constructor.name) {
        case 'MyError':
            console.log('Do custom handling')
        break;
        default:
            console.log('Another type of error')
    }
}

And with bluebird:

import { TypedError } from 'typed-error'
import * as Promise from 'bluebird'

class MyError extends TypedError {}

Promise.try(() => {
    throw new MyError()
})
.catch(MyError, (e) => {
    console.log('Do custom handling')
})
.catch(() => {
    console.log('Another type of error')
})

// Or
const MyErrorName = (e: Error) => e.name === 'MyError'
Promise.try(() => {
    throw new MyError()
})
.catch(MyErrorName, (e) => {
    console.log('Do custom handling')
})
.catch(() => {
    console.log('Another type of error')
})

// Or
const MyErrorConstructorName = (e: Error) => e.constructor.name === 'MyError'
Promise.try(() => {
    throw new MyError()
})
.catch(MyErrorConstructorName, (e) => {
    console.log('Do custom handling')
})
.catch(() => {
    console.log('Another type of error')
})

For coffeescript:

{ TypedError } = require 'typed-error'

class MyError extends TypedError

try
    throw new MyError()
catch e
    console.log(e instanceof MyError) # true
    console.log(e.name) # 'MyError'
    console.log(e.constructor.name) # 'MyError'
    console.log(e.stack) # <stack trace>

    if e instanceof MyError
        console.log('Do custom handling')
    else
        console.log('Another type of error')

    # Or
    switch e.name
        when 'MyError'
            console.log('Do custom handling')
        else
            console.log('Another type of error')

    # Or
    switch e.constructor.name
        when 'MyError'
            console.log('Do custom handling')
        else
            console.log('Another type of error')

And with bluebird:

Promise = require 'bluebird'
{ TypedError } = require 'typed-error'

class MyError extends TypedError

Promise.try ->
    throw new MyError()
.catch MyError, (e) ->
    console.log('Do custom handling')
.catch ->
    console.log('Another type of error')

# Or
MyErrorName = (e) -> e.name is 'MyError'
Promise.try ->
    throw new MyError()
.catch MyErrorName, (e) ->
    console.log('Do custom handling')
.catch ->
    console.log('Another type of error')

# Or
MyErrorConstructorName = (e) -> e.constructor.name is 'MyError'
Promise.try ->
    throw new MyError()
.catch MyErrorConstructorName, (e) ->
    console.log('Do custom handling')
.catch ->
    console.log('Another type of error')

balena-io-modules / typed-error

readme