Tutorial

❮ Previous Next ❯

JSON Object Literals

This is a JSON string:

'{"name":"John", "age":30, "car":null}'

Inside the JSON string there is a JSON object literal:

{"name":"John", "age":30, "car":null}

JSON object literals are surrounded by curly braces {}.

JSON object literals contains key/value pairs.

Keys and values are separated by a colon.

Keys must be strings, and values must be a valid JSON data type:

• a string

• a number

• an object

• an array

• a boolean

• null

Each key/value pair is separated by a comma.

JavaScript Objects

You can create a JavaScript object from a JSON object literal:

myObj = {"name":"John", "age":30, "car":null};

EXAMPLE ❯


                                myJSON = '{"name":"John", "age":30, "car":null}';<br />
myObj = JSON.parse(myJSON);

Accessing Object Values

You can access object values by using dot (.) notation:

Example:

const myJSON = '{"name":"John", "age":30, "car":null}';
const myObj = JSON.parse(myJSON);
x = myObj.name;

You can also access object values by using bracket ([]) notation:

EXAMPLE ❯


                                const myJSON = '{"name":"John", "age":30, "car":null}';<br />
const myObj = JSON.parse(myJSON);<br />
x = myObj["name"];

Looping an Object

You can loop through object properties with a for-in loop:

Example:

const myJSON = '{"name":"John", "age":30, "car":null}';
const myObj = JSON.parse(myJSON);

let text = "";
for (const x in myObj) {
text += x + ", ";
}

In a for-in loop, use the bracket notation to access the property values:

EXAMPLE ❯


                                const myJSON = '{"name":"John", "age":30, "car":null}';<br />
const myObj = JSON.parse(myJSON);<br />
<br />
let text = "";<br />
for (const x in myObj) {<br />
  text += myObj[x] + ", ";<br />
}<br />

❮ Previous Next ❯