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NodeJS - console.dir() Method

The Node.js console.dir() method is an inbuilt method of the Console class.

The Node.js console.dir() method of node.js returns the properties of a particular object. This method is used to display an interactive list of the properties of specific object in the terminal window. When called, it prints a hierarchical representation of the object's properties and values, allowing the user to quickly examine them without having to manually iterate over each property or value.

This is especially useful while debugging. This is because it's easier to view objects than entering individual properties and their associated values ​​into the console log.

Assume a boy is an object and he has some properties like name, age, school, marks, etc. To return the properties of the boy, we use console.dir() method of node.js. To get a better understanding let's look into the syntax and usage of the console.dir() method.

Syntax

Following is the syntax of the Node.js console.dir() method −

console.dir(object[, options])

Parameters

This method accepts only two parameters. The same are described below.

  • object − This parameter specifies an object that has to be returned.

Following are the optional parameters, let's look into them.

  • showHidden − This is a Boolean value. If it is true, then the non-enumerable and symbol properties of the object will be shown.

  • depth − This is a number. This will let us print the levels of the specified object. By default, the depth is 2. If we want to get all the levels of the object pass null.

  • colors − This is a Boolean value. If we pass true, the property values will be displayed in ANSI color codes. We can customize the colors. By default the value is false (No ANSI colors)

Return value

This method returns the properties of a specified object.

Example

The Node.js console.dir() method of node.js will accept only one object parameter.

In the example below, we are creating an object with enumerable properties. To return the object properties, we are calling the Node.js console.dir() method with object name passing as a parameter.

var object = {
   Name : "Nik",
   Age : 31,
   Eyes :"black",
   height : 5.2,
   weight : 70
}
console.dir(object);

Output

As we can see in the below output when we call the console.dir() method by passing the object name as a parameter, will list out the object's enumerable properties.

{ Name: 'Nik', Age: 31, Eyes: 'black', height: 5.2, weight: 70 }

Example

In the example below, we are creating a 4-leveled object. To return the object properties, we are calling the console.dir() method with object name passing as a parameter.

Note − By default, the console.dir() method can only go up to 2 levels.

var object = { // level 0 start
   firstname : "James",
   lastname : "Anderson",
   Initial : function() {
      return this.firstname[0] + this.lastname[0];
   },
   attrributes: { // level 1 start
      age : 34,
      school : "High school",
      hobbies : { // level 2 start
         favourite : { // level 3 start
            sport : "football",
            book : "Nothing"
         },
         RecentlyPlayed : {
            game : "cricket",
            videogame : "GTA5"
         } // level 3 ends
      } // level 2 ends   
   } // level 1 ends
} // level 0 ends

console.dir(object);

Output

As we can see in the below output, we got the object's properties as output up to 2 levels. So, to get all the object's properties we need to use the depth parameter. To know the usage of the depth parameter, look into the next example.

{
   firstname: 'James',
   lastname: 'Anderson',
   Initial: [Function: Initial],
   attrributes: {
      age: 34,
      school: 'High school',
      hobbies: { favourite: [Object], RecentlyPlayed: [Object] }
   }
}

Example

The console.dir() method of node.js will also accept some additional parameters like showHidden, depth, and colors, and we are using the depth optional parameter in the example.

In the example below,

  • We are creating a 4-leveled object.

  • To return the object properties, we are calling the console.dir() method with object name passing as a parameter.

  • By default, it only returns the object's properties up to 2 levels.

  • We are trying to get the object's properties of all the levels by using the depth parameter.

var object = { // level 0 start
   firstname : "James",
   lastname : "Anderson",
   Initial : function() {
      return this.firstname[0] + this.lastname[0];
   },
   attrributes: { // level 1 start
      age : 34,
      school : "High school",
      hobbies : { // level 2 start
         favourite : { // level 3 start
            sport : "football",
            book : "Nothing"
         },
         RecentlyPlayed : {
            game : "cricket",
            videogame : "GTA5"
         } // level 3 ends
      } // level 2 ends   
   } // level 1 ends
} // level 0 ends

console.dir(object, {depth: null, showHidden: true});

Output

As we can see in the below output, the object's properties of all levels got printed. We have done it by declaring depth as null.

{
  firstname: 'James',
  lastname: 'Anderson',
  Initial: [Function: Initial] {
    [length]: 0,
    [name]: 'Initial',
    [arguments]: null,
    [caller]: null,
    [prototype]: Initial { [constructor]: [Circular] }
  },
  attrributes: {
    age: 34,
    school: 'High school',
    hobbies: {
      favourite: { sport: 'football', book: 'Nothing' },
      RecentlyPlayed: { game: 'cricket', videogame: 'GTA5' }
    }
  }
}

Example

The console.dir() method of node.js will also accept some additional parameters like showHidden, depth, and colors and we are using showHidden optional parameter in the example.

In the example below,

  • We are creating a 4-leveled object.

  • To return the object properties, we are calling the console.dir() method with object name passing as a parameter.

  • We are passing the showHidden parameter as true, it will show the hidden object's non-enumerable and symbol properties.

var object = { // level 0 start
   firstname : "James",
   lastname : "Anderson",
   Initial : function() {
      return this.firstname[0] + this.lastname[0];
   },
   attrributes: { // level 1 start
      age : 34,
      school : "High school",
      hobbies : { // level 2 start
         favourite : { // level 3 start
            sport : "football",
            book : "Nothing"
         },
         RecentlyPlayed : {
            game : "cricket",
            videogame : "GTA5"
         } // level 3 ends
      } // level 2 ends   
   } // level 1 ends
} // level 0 ends

console.dir(object, {depth: null, showHidden: true});

Output

As we can see in the output, the hidden properties are shown the output along with the object's properties.

{
   firstname: 'James',
   lastname: 'Anderson',
   Initial: <ref *1> [Function: Initial] {
      [length]: 0,
      [name]: 'Initial',
      [arguments]: null,
      [caller]: null,
      [prototype]: { [constructor]: [Circular *1] }
   },
   attrributes: {
      age: 34,
      school: 'High school',
      hobbies: {
         favourite: { sport: 'football', book: 'Nothing' },
         RecentlyPlayed: { game: 'cricket', videogame: 'GTA5' }
      }
   }
}

Example

The console.dir() method of node.js will also accept some additional parameters like showHidden, depth, and colors, and we are using colors as an optional parameter in the example.

In the example below,

  • We are creating a 4-leveled object.

  • To return the object properties, we are calling the console.dir() method with object name passing as a parameter.

  • We are changing colors (With ANSI color codes) of the output by passing the colors parameter as true. By default, the value is false (No colors).

var object = {  // level 0 start
   firstname : "James",
   lastname : "Anderson",
   Initial : function() {
      return this.firstname[0] + this.lastname[0];
   },
   attrributes: { // level 1 start
      age : 34,
      school : "High school",
      hobbies : { // level 2 start
         favourite : { // level 3 start
            sport : "football",
            book : "Nothing"
         },
         RecentlyPlayed : {
            game : "cricket",
            videogame : "GTA5"
         } // level 3 ends
      } // level 2 ends   
   } // level 1 ends
} // level 0 ends

console.dir(object, {depth: null, showHidden: true, colors: true});

Output

As we can see in the output, we got one color for the object's string properties and another color for the object's integer properties.

{
   firstname: 'James',
   lastname: 'Anderson',
   Initial: <ref *1> [Function: Initial] {
      [length]: 0,
      [name]: 'Initial',
      [arguments]: null,
      [caller]: null,
      [prototype]: { [constructor]: [Circular *1] }
   },
   attrributes: {
      age: 34,
      school: 'High school',
      hobbies: {
         favourite: { sport: 'football', book: 'Nothing' },
         RecentlyPlayed: { game: 'cricket', videogame: 'GTA5' }
      }
   }
}
nodejs_console_module.htm
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