on-error

on-error

Handle callback errors without the if blocks.

On error, execute separate error handler function, or emit it. On no error, execute regular callback
(with or without error stripped).

example

// if error handleIt, otherwise...
doSomething(onError(handleIt).otherwise(function (message) {
    console.log('will see this: %s', message)
}))

failToDoSomething(onError(handleIt).otherwise(function (message) {
    console.log('will NOT see this: %s', message)
}))

// if error handleIt, and always...
failToDoSomething(onError(handleIt).always(function (message) {
    console.log('will see this too: %s', message)
}))

// if error handleIt, and always (include error for always func)...
failToDoSomething(onError(handleIt).alwaysWithError(function (err, message) {
    console.log('will see this too (with the error): %s, %s', err, message)
}))

// maybe we want to emit the error instead...
var emitter = new EventEmitter().on('error', console.log)
failToDoSomething(onError.emit(emitter).otherwise(function (message) {
    // will not get here
}))

api

var onError = require('on-error')

onError(cb)

Returns a function that when called with a truthy first argument, will execute cb with said argument.

onError.emit(emitter)

Returns a function that when called with a truthy first argument, will emit error on the provided event emitter with said argument.

onError(cb1).otherwise(cb2)

Returns a function that when called with a truthy first argument, will execute cb1 with said argument. When executed with a non-truthy 1st argument, cb2 will instead be executed with the error argument stripped.

.otherwise may always be chained from onError.emit()

onError(cb1).always(cb2)

Returns a function that when called with a truthy first argument, will execute cb1 with said argument. In addition, cb2 will always be executed with the error argument stripped.

.always may always be chained from onError.emit()

onError(cb1).alwaysWithError(cb2)

Returns a function that when called with a truthy first argument, will execute cb1 with said argument. In addition, cb2 will always be executed with the error argument in-tact.

.alwaysWithError may always be chained from onError.emit()

testing

npm test [--dot | --spec] [--coverage]

Alternatively, only run test files matching a certain pattern by prefixing the command with grep=pattern. Example: grep=init npm test

Open an html coverage report after running tests with npm run view-cover or npm run vc