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JavaScript•Objects, Classes, and Advanced Patterns

JavaScript Display Objects

How to Display JavaScript Objects?

Displaying a JavaScript object will output [object Object] .

Example

// Create an Object
const person = {
  name: "John", age: 30, city: "New York"
};
let text = person;

Why do I See [object Object]?

[Object Object] appears when you try to put an object (a data structure with properties) into a context where a string is expected .

[Object Object] how JavaScript deals with this situation.

Some solutions to display JavaScript objects are: Displaying the Object Properties by name Displaying the Object Properties in a Loop Displaying the Object using Object.values() Displaying the Object using JSON.stringify()

  • Displaying the Object Properties by name
  • Displaying the Object Properties in a Loop
  • Displaying the Object using Object.values()
  • Displaying the Object using JSON.stringify()

Displaying Object Properties

The properties of an object can be added in a string:

Example

// Create an Object
const person = {
  name: "John", age: 30, city: "New York"
};
// Add Properties
let text = person.name + "," + person.age + "," + person.city;

Using a For .. In Loop

The properties of an object can be collected in a loop:

Example

// Create an Object
const person = {
  name: "John", age: 30, city: "New York"
};
// Build a Text
let text = "";
for (let x in person) {
  text += person[x] + " ";
};

You must use person[x] in the loop.

person.x will not work (Because x is the loop variable).

Using Object.values()

Object.values() creates an array from the property values:

Runnable example

// Create an Object
const person = {
  name: "John", age: 30, city: "New York"
};
// Create an Array
const myArray = Object.values(person);
// Stringify the Array
let text = myArray.toString();

Using Object.entries()

Object.entries() makes it simple to use objects in loops:

Example

const fruits = {Bananas:300, Oranges:200, Apples:500};
let text = "";
for (let [fruit, value] of Object.entries(fruits)) {
  text += fruit + ": " + value + "<br>";
}

Using JSON.stringify()

JavaScript objects can be converted to a string with JSON method JSON.stringify() .

JSON.stringify() is included in JavaScript and supported in all browsers.

The result will be a string written in JSON notation:

{"name":"John","age":50,"city":"New York"}

Example

// Create an Object
const person = {
  name: "John", age: 30, city: "New York"
};
// Stringify Object
let text = JSON.stringify(person);

See Also

What are JavaScript Objects?

What are Object Properties?

What are Object Methods?

What is this in Objects?

What is an Object Constructor?

Advanced Chapters

JavaScript Object Definitions

JavaScript Object Advanced this

JavaScript Object Iterations

JavaScript Object Getters & Setters

JavaScript Object Management

JavaScript Object Protection

JavaScript Object Prototypes

JavaScript Object Reference

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