shallow clone Error Object

思いつきでエラーのクローン。使い道とか全く思いつかないけど

cloneError.js

;(function (global) {
    'use strict'

     var isBrowser = !! global.self
     var isWorker  = !! global.WorkerLocation
     var isNodeJS  = !! global.global

     function cloneError (err) {
        if (!(err instanceof Error)) throw new TypeError(
            ({}).toString.apply(err) + ' not instanceof Error')
        return new global[err.name](err.message)
     }

     isNodeJS ? (module.exports = cloneError)
               : (global['cloneError'] = cloneError)
})(this.self || global)

error.test.js

var test = require('tape')
var cloneError = require('cloneError')

test('shallow clone "Error"', function (t) {
    var error = new URIError('not found')
    var clone = cloneError(error)

    t.equal(error.toString(), clone.toString(), '.toString() -> ' + clone.toString())
    t.not(error, clone, 'originalError !== clonedError')
    t.end()
})

tap --tap error.test.js してみる

TAP version 13
# error.test.js
# TAP version 13
# shallow clone "Error"
ok 1 .toString() -> URIError: not found
ok 2 originalError !== clonedError
# tests 2
# pass  2
# ok
ok 3 ./error.test.js


1..3
# tests 3
# pass  3

# ok