makeerror.js
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var tmpl = require('tmpl')
module.exports = makeError
function BaseError() {}
BaseError.prototype = new Error()
BaseError.prototype.toString = function() {
return this.message
}
/**
* Makes an Error function with the signature:
*
* function(message, data)
*
* You'll typically do something like:
*
* var UnknownFileTypeError = makeError(
* 'UnknownFileTypeError',
* 'The specified type is not known.'
* )
* var er = UnknownFileTypeError()
*
* `er` will have a prototype chain that ensures:
*
* er instanceof Error
* er instanceof UnknownFileTypeError
*
* You can also do `var er = new UnknownFileTypeError()` if you really like the
* `new` keyword.
*
* @param String The name of the error.
* @param String The default message string.
* @param Object The default data object, merged with per instance data.
*/
function makeError(name, defaultMessage, defaultData) {
defaultMessage = tmpl(defaultMessage || '')
defaultData = defaultData || {}
if (defaultData.proto && !(defaultData.proto instanceof BaseError))
throw new Error('The custom "proto" must be an Error created via makeError')
var CustomError = function(message, data) {
if (!(this instanceof CustomError)) return new CustomError(message, data)
if (typeof message !== 'string' && !data) {
data = message
message = null
}
this.name = name
this.data = data || defaultData
if (typeof message === 'string') {
this.message = tmpl(message, this.data)
} else {
this.message = defaultMessage(this.data)
}
var er = new Error()
this.stack = er.stack
if (this.stack) {
// remove TWO stack level:
if (typeof Components !== 'undefined') {
// Mozilla:
this.stack = this.stack.substring(this.stack.indexOf('\n') + 2)
} else if (typeof chrome !== 'undefined' || typeof process !== 'undefined') {
// Google Chrome/Node.js:
this.stack = this.stack.replace(/\n[^\n]*/, '')
this.stack = this.stack.replace(/\n[^\n]*/, '')
this.stack = (
this.name +
(this.message ? (': ' + this.message) : '') +
this.stack.substring(5)
)
}
}
if ('fileName' in er) this.fileName = er.fileName
if ('lineNumber' in er) this.lineNumber = er.lineNumber
}
CustomError.prototype = defaultData.proto || new BaseError()
delete defaultData.proto
return CustomError
}