on-error

on-error

Handle callback errors by executing an error handler function, or emitting the error, instead of or in addition to executing the callback.

example

var onError = require('on-error')

function fail (cb) {
    cb(new Error('failed'))
}

function succeed (cb) {
    cb(null, 'success')
}

Using error handler function:

function handleIt (err) {
    console.error(err)
}

fail(onError(handleIt, function (status) {
    console.log('will not see this')
}))

fail(onError(handleIt, {alwaysCall: true}, function (err, status) {
    // When always call specified, err is passed
    console.log('will see this')
}))

succeed(onError(handleIt, function (status) {
    // Gets called with status of success
    console.log(status)
}))

Using emitter:

var EventEmitter = require('events').EventEmitter
var emitter = new EventEmitter().on('error', function (err) {
    console.error(err)
})

fail(onError.emit(emitter, function (status) {
    console.log('will not see this')
}))

api

onError

var onError = require('on-error')

var wrappedCb = onError(errHandler [, options, cb])

Returns a function that when called with a truthy first argument, will execute the errHandler with the 1st (error) argument supplied to the wrappedCb. If the option alwaysCall is define, the provided cb will be executed in all cases with all arguments supplied to wrappedCb, otherwise if the 1st argument to wrappedCb is falsey, the supplied cb will be executed with all but the 1st argument supplied to wrappedCb.

If no callback cb is provided, then the generated callback will simply execute errHandler when called with a non-falsey 1st argument.

options:

• alwaysCall: true or false - if true, the provided callback cb will always be called (and include the 1st argument), otherwise it will only be called when a the first argument is falsey (and without the 1st argument)

var wrappedCb = onError.emit(emitter [, options, cb])

Same behaviour as above, except errors will be emitted to emitter instead of passed to an error handler function. All other options and arguments are the same.

testing

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

options

• --dot - output test results as dots instead of tap
• --spec - output test results as spec instead of tap
• --coverage - display text cover report
• --testling - run tests in browser via testling (cannot be used with --coverage and expects both browserify and testling to be installed globally)

patterns

Only run test files matching a certain pattern by prefixing the test command with grep=pattern. Example:

grep=connect npm test --dot

html coverage report

Open it with npm run view-cover or npm run vc