What does object Object mean

Question

I am trying to alert a returned value from a function and I get this in the alert    object Object      Here is the JavaScript code    lt script type  text javascript  gt    function      var  main       main         1       1         2       2      2 hide       hide div 2 when the page is loaded   main click function           1 toggle         2 toggle              senddvd   click function         alert  hello       var a whichIsVisible       alert whichIsVisible          function whichIsVisible         if    1 is   hidden    return  1      if    2 is   hidden    return  2             lt  script gt    whichIsVisible is the function which I am trying to check on

User · Answer

You have a javascript object   1 and  2 are jquery objects  maybe use alert  1 text     to get text or alert  1 attr  id    etc     you have to treat  1 and  2 like jQuery objects

User · Answer

The default conversion from an object to string is   object Object     As you are dealing with jQuery objects  you might want to do  alert whichIsVisible   0  id     to print the element s ID   As mentioned in the comments  you should use the tools included in browsers like Firefox or Chrome to introspect objects by doing console log whichIsVisible    instead of alert   Sidenote  IDs should not start with digits

User · Answer

You are trying to return an object  Because there is no good way to represent an object as a string  the object s  toString   value is automatically set as   object Object

User · Answer

It s the value returned by that object s toString   function     I understand what you re trying to do  because I answered your question yesterday about determining which div is visible     The whichIsVisible   function returns an actual jQuery object  because I thought that would be more programmatically useful  If you want to use this function for debugging purposes  you can just do something like this   function whichIsVisible v2         if    1 is   hidden    return   1       if    2 is   hidden    return   2       That said  you really should be using a proper debugger rather than alert   if you re trying to debug a problem  If you re using Firefox  Firebug is excellent  If you re using IE8  Safari  or Chrome  they have built-in debuggers

User · Answer

object Object  is the default toString representation of an object in javascript   If you want to know the properties of your object  just foreach over it like this   for var property in obj        alert property         obj property        In your particular case  you are getting a jQuery object  Try doing this instead       senddvd   click function         alert  hello       var a whichIsVisible       alert whichIsVisible   attr  id           This should alert the id of the visible element

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Consider the following example  const foo       foo Symbol toStringTag     quot bar quot   console log  quot  quot    foo    Which outputs  object bar   Basically  any object in javascript can define a property with the tag Symbol toStringTag and override the output  Behind the scenes construction of a new object in javascript prototypes from some object with a  quot toString quot  method  The default object provides this method as a property  and that method internally invokes the tag to determine how to coerce the object to a string  If the tag is present  then it s used  if missing you get  quot Object quot   Should you set Symbol toStringTag  Maybe  But relying on the string always being  object Object  for  quot true quot  objects is not the best idea

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Basics  You may not know it but  in JavaScript  whenever we interact with string  number or boolean primitives we enter a hidden world of object shadows and coercion   string  number  boolean  null  undefined  and symbol   In JavaScript there are 7 primitive types  undefined  null  boolean  string  number  bigint and symbol  Everything else is an object  The primitive types boolean  string and number can be wrapped by their object counterparts  These objects are instances of the Boolean  String and Number constructors respectively   typeof true     boolean  typeof new Boolean true      object   typeof  this is a string      string  typeof new String  this is a string       object   typeof 123     number  typeof new Number 123      object    If primitives have no properties  why does  this is a string  length return a value   Because JavaScript will readily coerce between primitives and objects  In this case the string value is coerced to a string object in order to access the property length  The string object is only used for a fraction of second after which it is sacrificed to the Gods of garbage collection     but in the spirit of the TV discovery shows  we will trap the elusive creature and preserve it for further analysis     To demonstrate this further consider the following example in which we are adding a new property to String constructor prototype   String prototype sampleProperty   5  var str    this is a string   str sampleProperty                5   By this means primitives have access to all the properties  including methods  defined by their respective object constructors   So we saw that primitive types will appropriately coerce to their respective Object counterpart when required    Analysis of toString   method  Consider the following code  var myObj       lhs  3  rhs  2   var myFunc     function     var myString    This is a sample String   var myNumber   4  var myArray     2  3  5    myObj toString             object Object   myFunc toString           function      myString toString         This is a sample String  myNumber toString         4  myArray toString          2 3 5    As discussed above  what s really happening is when we call toString   method on a primitive type  it has to be coerced into its object counterpart before it can invoke the method  i e  myNumber toString   is equivalent to Number prototype toString call myNumber  and similarly for other primitive types   But what if instead of primitive type being passed into toString   method of its corresponding Object constructor function counterpart  we force the primitive type to be passed as parameter onto toString   method of Object function constructor  Object prototype toString call x     Closer look at Object prototype toString    As per the documentation   When the toString method is called  the following steps are taken         If the this value is undefined  return   object Undefined      If the this value is null  return   object Null      If this value is none of the above  Let O be the result of calling toObject passing the this value as the argument    Let class be the value of the   Class   internal property of O    Return the String value that is the result of concatenating the three Strings   object    class  and           Understand this from the following example  var myObj          lhs  3  rhs  2   var myFunc        function     var myString       This is a sample String   var myNumber      4  var myArray        2  3  5   var myUndefined   undefined  var myNull        null   Object prototype toString call myObj               object Object   Object prototype toString call myFunc              object Function   Object prototype toString call myString            object String   Object prototype toString call myNumber            object Number   Object prototype toString call myArray             object Array   Object prototype toString call myUndefined         object Undefined   Object prototype toString call myNull              object Null     References  https   es5 github io x15 2 html x15 2 4 2 https   es5 github io x9 html x9 9 https   javascriptweblog wordpress com 2010 09 27 the-secret-life-of-javascript-primitives

User · Answer

object Object  is the default string representation of a JavaScript Object  It is what you ll get if you run this code   alert          object Object    You can change the default representation by overriding the toString method like so   var o    toString  function    return  foo      alert o      foo

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As others have noted  this is the default serialisation of an object  But why is it  object Object  and not just  object    That is because there are different types of objects in Javascript    Function objects  stringify function       -   object Function  Array objects  stringify     -   object Array  RegExp objects stringify  x   -   object RegExp  Date objects stringify new Date  -   object Date      several more     and Object objects  stringify     -   object Object    That s because the constructor function is called Object  with a capital  O    and the term  object   with small  o   refers to the structural nature of the thingy   Usually  when you re talking about  objects  in Javascript  you actually mean  Object objects   and not the other types   where stringify should look like this     function stringify  x        console log Object prototype toString call x

User · Answer

You can see value inside   object Object  like this  Alert alert   JSON stringify userDate        Try like this      realm write      gt           const userFormData   realm create  User           user email  value username         user password  value password                            const userDate   realm objects  User   filtered  user email     0   value username toString             Alert alert   JSON stringify userDate        reference  https   off tokyo blog react-native-object-object

User · Answer

I think the best way out is by using JSON stringify   and passing your data as param  alert JSON stringify whichIsVisible

[javascript] What does [object Object] mean?

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