substance/util/SubstanceError.js

Substance is a JavaScript library for web-based content editing. It provides building blocks for realizing custom text editors and web-based publishing systems.

/*
  Custom error object for all Substance related errors

  @example

  ```js
  import Err from 'substance/util/SubstanceError'
  throw new Err('Document.SelectionUpdateError', {message: 'Could not update selection.'})
  ```

  For better inspection allows you to pass a cause (the error that caused the error).
  That way we can attach context information on each level and we can also ensure
  security, by not passing the cause-chain to the client.

  Resources:
    http://www.bennadel.com/blog/2828-creating-custom-error-objects-in-node-js-with-error-capturestacktrace.htm
    https://gist.github.com/justmoon/15511f92e5216fa2624b
    https://github.com/davepacheco/node-verror/blob/master/lib/verror.js
*/

class SubstanceError extends Error {
  constructor(name, options) {
    super(name, options)
    this.name = name
    this.message = options.message
    this.info = options.info
    this.errorCode = options.errorCode
    this.cause = options.cause

    if (Error.captureStackTrace) {
      Error.captureStackTrace(this, (SubstanceError))
    }
  }

  inspect() {
    var parts = []

    // This gives us a full node.js error including error name + message + stack trace
    parts.push(this.stack)

    // We just print additional info here
    if (this.info) {
      parts.push(this.info + '. ')
    }

    // We also print the cause in the same way
    if (this.cause) {
      parts.push('\nCaused by: ')

      if (this.cause.inspect) {
        // If cause is again a Substance error
        parts.push(this.cause.inspect())
      } else {
        // If not we just use Error.toString
        parts.push(this.cause.toString())
      }
    }
    return parts.join('')
  }
}


SubstanceError.fromJSON = function(err) {
  if (!err) return null
  var error = new SubstanceError(err.name, {
    message: err.message,
    info: err.info,
    errorCode: err.errorCode,
    cause: SubstanceError.fromJSON(err.cause)
  })
  return error
}

export default SubstanceError