Errors formats.

error-formats.js

// Single error.
{
  error: "a is bad"
}

// Single detailed error.
{
  error: {
    message : 'a is bad', 
    text    : 'a is bad because of ...',
    code    : ' > error in line ....'
  }
}

// Multiple errors.
{
  errors: [
    "a is bad", 
    "b is bad"
  ]
}

// Multiple detailed errors.
{
  errors: [
    {
      message : 'a is bad',       
      code    : ' > error in line ....'
    },
    {
      message : 'b is bad', 
      code    : ' > error in line ....'
    }
  ]
}

// Detailed message.
// All attributes are optional.
{
  // Simple text message.
  message : 'b is bad', 
  
  // Detailed textual description.
  text    : 'b is bad because of ...',
  
  // Code snipped.
  code    : ' > error in line ....'
  
  // May be more in future ...
}

{
 errors: [
   "a is bad",
   "b is bad"
 ],
isPreformatted: true
}