JSON Arrays

JSON arrays are enclosed in square brackets.

Just like in JavaScript, an array can contain objects.

“employees”:[
  {“firstName”:“John”, “lastName”:“Doe”},
  {“firstName”:“Anna”, “lastName”:“Smith”},
  {“firstName”:“Peter”, “lastName”:“Jones”}
]

In the example above, the employees object is an array containing three objects.

Each object represents a person’s record, with a first name and a last name.

Converting a JSON Text to a JavaScript Object

A common use of JSON is to retrieve data from a web server and display it on a web page.

For simplicity, this can be demonstrated using a string that contains JSON syntax.

First, create a JavaScript string with JSON format.

let text = ‘{ “employees” : [‘ +
‘{ “firstName”:”John” , “lastName”:”Doe” },’ +
‘{ “firstName”:”Anna” , “lastName”:”Smith” },’ +
‘{ “firstName”:”Peter” , “lastName”:”Jones” } ]}’;

Next, use the JavaScript built-in function JSON.parse() to convert the string into a JavaScript object.

const obj = JSON.parse(text);

Finally, use the newly created JavaScript object in your page.

Example

<p id=”demo”></p>

<script>
document.getElementById(“demo”).innerHTML =
obj.employees[1].firstName + ” “ + obj.employees[1].lastName;
</script>