See hidden property of Object

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I am trying to handle errors in node.js.

When I run console.log(error) I get:

TypeError: Cannot read property 'id' of undefined
at (/.../schema.js:72:20)
at <anonymous>
at process._tickCallback (internal/process/next_tick.js:189:7)

But if I try to run Object.keys(error) I get [] empty array. For different errors I do get ['message', 'code', 'type', 'errno'].

When trying to access the property of the above written error then error.message still works.

Is it possible despite those properties being hidden, to get their names?

Object.keys returns only own enumerable properties. If it returns nothing, this means that message is either inherited from a prototype or is non-enumerable, the latter is the case for TypeError properties.

Non-enumerable properties can be listed with Object.getOwnPropertyNames(error).

Inherited properties can be retrieved by iterating over prototypes:

let proto = error;

while (proto) {
  proto = Object.getPrototypeOf(proto);

Hiding properties in JavaScript, Sometimes, you want to define a property on an object that can't ways to create what might be called "hidden properties", without looking… This makes the property not show up when you enumerate the object's properties  Summary: Learn how to use Windows PowerShell to display hidden properties from an object. How can I see if there are any hidden properties on an object I have returned from Windows PowerShell? Use the -Force parameter with either Format-List or Format-Table, for example: Get-ChildItem C: | Format-List * -Force

The TypeError is not an array/map, is an exception instance well defined:

if (e instanceof TypeError)


catch (e) {
    if (e instanceof TypeError) {
      // Output expected TypeErrors.
      //Here try to get the information you need here
    } else {
      // Output unexpected Errors.
      logging.log(e, false);

Take a look:

Object.getOwnPropertyNames(), The HTMLElement property hidden is a Boolean which is true if the element is hidden; otherwise the value is false . This is quite different  Basically, visibility: hidden makes the element invisible to the browser, but it still remains in place and takes up the same space had you not hidden it. For example, if you place a DIV on your page and use CSS to give it the dimensions of 100 by 100 pixels, the visibility: hidden property will hide the DIV , but the text following it will act

May be it is not true but I think problem in next...

You are using solr-node-client library. This library depended on bluebird library. Last library create own TypeError class like this code:

function subError(nameProperty, defaultMessage) {
    function SubError(message) {
        if (!(this instanceof SubError)) return new SubError(message);
        notEnumerableProp(this, "message",
            typeof message === "string" ? message : defaultMessage);
        notEnumerableProp(this, "name", nameProperty);
        if (Error.captureStackTrace) {
            Error.captureStackTrace(this, this.constructor);
        } else {
    inherits(SubError, Error);
    return SubError;

And this code set message and name attributes as not enumerable.

HTMLElement.hidden, The visibility property allows the author to show or hide an element. It is similar to the property: = "visible|hidden|collapse|initial|inherit"  Range.Hidden property (Excel) 05/11/2019; 2 minutes to read; In this article. Returns or sets a Variant value that indicates if the rows or columns are hidden. Syntax. expression.Hidden. expression A variable that represents a Range object. Remarks. Set this property to True to hide a row or column. The specified range must span an entire

Private properties in JavaScript, Again, investigating hidden class closely, you can see the properties type as DictionaryProperties and dict_index in properties store. V8 tries to  Find the object with the label that matches the hidden front panel object. Right-click the terminal and select Show Control from the shortcut menu if the object is a control or Show Indicator if the object is an indicator. You also can use the Visible property to display controls and indicators programmatically.

HTML DOM Style visibility Property, How can I see if there are any hidden properties on an object I have returned from Windows PowerShell? Hey, Scripting Guy! Answer Use the -  For all versions of Cognos 8/10, each object has a disabled property. If an object is disabled, it will be hidden from the user unless they have “write” permission for the object. Hiding objects with the Hidden property 8.1 to 8.3. In ealier versions of Cognos 8 an object was hidden from the user if the object’s hidden property was set.

The Secrets of JavaScript Object & Performance Optimization, The writable properties of a object correspond to Description: '' DetailedDescription: '' Hidden: 0 Sealed: 0 For example, find the object for the Category property of the  Browsers should not display elements that have the hidden attribute specified. The hidden attribute can also be used to keep a user from seeing an element until some other condition has been met (like selecting a checkbox, etc.). Then, a JavaScript could remove the hidden attribute, and make the element visible.