node/deps/npm/node_modules/create-error-class/index.js

'use strict';
var captureStackTrace = require('capture-stack-trace');

function inherits(ctor, superCtor) {
	ctor.super_ = superCtor;
	ctor.prototype = Object.create(superCtor.prototype, {
		constructor: {
			value: ctor,
			enumerable: false,
			writable: true,
			configurable: true
		}
	});
}

module.exports = function createErrorClass(className, setup) {
	if (typeof className !== 'string') {
		throw new TypeError('Expected className to be a string');
	}

	if (/[^0-9a-zA-Z_$]/.test(className)) {
		throw new Error('className contains invalid characters');
	}

	setup = setup || function (message) {
		this.message = message;
	};

	var ErrorClass = function () {
		Object.defineProperty(this, 'name', {
			configurable: true,
			value: className,
			writable: true
		});

		captureStackTrace(this, this.constructor);

		setup.apply(this, arguments);
	};

	inherits(ErrorClass, Error);

	return ErrorClass;
};