JSON.parse()

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JSON.parse()


A common use of JSON is to exchange data to/from a web server.
When receiving data from a web server, the data is always a string.
Parse the data with JSON.parse(), and the data becomes a JavaScript object.

Example - Parsing JSON
Imagine we received this text from a web server:


'{"name":"John", "age":30, "city":"New York"}'


Use the JavaScript function JSON.parse() to convert text into a JavaScript object:


const obj = JSON.parse('{"name":"John", "age":30, "city":"New
York"}');



Make sure the text is in JSON format, or else you will get a syntax error.

Use the JavaScript object in your page:

Example


<p id="demo"></p>

<script>
document.getElementById("demo").innerHTML = obj.name;
</script>
Try it Yourself »


Array as JSON
When using the JSON.parse() on a JSON derived from an array, the method will
return a JavaScript array, instead of a JavaScript object.

Example

const text = '["Ford", "BMW", "Audi", "Fiat"]';
const myArr = JSON.parse(text);

Try it Yourself »








Exceptions
Parsing Dates
Date objects are not allowed in JSON.
If you need to include a date, write it as a string.
You can convert it back into a date object later:

Example
Convert a string into a date:

const text =
'{"name":"John", "birth":"1986-12-14", "city":"New York"}';
const obj = JSON.parse(text);obj.birth = new Date(obj.birth);
document.getElementById("demo").innerHTML = obj.name + ", " + obj.birth;
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Or, you can use the second parameter, of the JSON.parse() function, called reviver.
The reviver parameter is a function that checks each property,
before returning the value.

Example
Convert a string into a date, using the reviver function:

const text =
'{"name":"John", "birth":"1986-12-14", "city":"New York"}';
const obj = JSON.parse(text, function (key, value) {  if
(key == "birth") {    return new
Date(value);  } else {   
return value;  }});
document.getElementById("demo").innerHTML = obj.name + ", " + obj.birth;
Try it Yourself »

Parsing Functions
Functions are not allowed in JSON.
If you need to include a function, write it as a string.
You can convert it back into a function later:

Example
Convert a string into a function:

const text =
'{"name":"John", "age":"function () {return
30;}", "city":"New York"}';
const obj = JSON.parse(text);obj.age = eval("(" + obj.age + ")");
document.getElementById("demo").innerHTML = obj.name + ", " +
obj.age();
Try it Yourself »


You should avoid using functions in JSON, the functions will lose their scope,
and you would have to use eval() to convert them back into functions.













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Reference: https://www.w3schools.com/js/js_json_parse.asp