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 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] + " ";
};
Note: 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:
// 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.
Note: 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);
Note: See Also: What are JavaScript Objects? What are Object Properties? What are Object Methods? What is this in Objects? What is an Object Constructor?
Note: 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
