json-parse-function-javascript.md

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JSON.parse Function (JavaScript) | Microsoft Docs		01/18/2017	windows-client-threshold			devlang-javascript		language-reference	JSON.parse	JavaScript TypeScript DHTML	parse JSON method JSON.parse method	20f00d31-5ab5-4c3c-ab49-2534fc39a9b4	41	mikejo5000	mikejo	ghogen

JSON.parse Function (JavaScript)

Converts a JavaScript Object Notation (JSON) string into an object.

Syntax

JSON.parse(text [, reviver])  

Parameters

text
Required. A valid JSON string.

reviver
Optional. A function that transforms the results. This function is called for each member of the object. If a member contains nested objects, the nested objects are transformed before the parent object. For each member, the following occurs:

• If reviver returns a valid value, the member value is replaced with the transformed value.

• If reviver returns the same value it received, the member value is not modified.

• If reviver returns null or undefined, the member is deleted.

Return Value

An object or array.

Exceptions

If this function causes a [!INCLUDEjavascript] parser error (such as "SCRIPT1014: Invalid character"), the input text does not comply with JSON syntax. To correct the error, do one of the following:

• Modify the text argument to comply with JSON syntax. For more information, see the BNF syntax notation of JSON objects.

  For example, if the response is in JSONP format instead of pure JSON, try this code on the response object:

  var fixedResponse = response.responseText.replace(/\\'/g, "'");  
  var jsonObj = JSON.parse(fixedResponse);  

• Make sure that the text argument was serialized by a JSON-compliant implementation such as JSON.stringify.

• Run the text argument in a JSON validator such as JSLint to help identify syntax errors.

Example

The following example uses JSON.parse to convert a JSON string to an object.

var jsontext = '{"firstname":"Jesper","surname":"Aaberg","phone":["555-0100","555-0120"]}';  
var contact = JSON.parse(jsontext);  
document.write(contact.surname + ", " + contact.firstname);  
document.write(contact.phone[1]);  
// Output:  
// Aaberg, Jesper  
// 555-0100  

Example

The following example converts an array to a JSON string by using JSON.stringify, and then converts the string back to an array by using JSON.parse.

var arr = ["a", "b", "c"];  
var str = JSON.stringify(arr);  
document.write(str);  
document.write ("<br/>");  
  
var newArr = JSON.parse(str);  
  
while (newArr.length > 0) {  
    document.write(newArr.pop() + "<br/>");  
}  
  
// Output:  
// ["a","b","c"]  
// c  
// b  
// a  

Example

The reviver function is often used to transform JSON representation of International Organization for Standardization (ISO) date strings into Coordinated Universal Time (UTC) format Date objects. This example uses JSON.parse to deserialize an ISO-formatted date string. The dateReviver function returns Date objects for members that are formatted like ISO date strings.

var jsontext = '{ "hiredate": "2008-01-01T12:00:00Z", "birthdate": "2008-12-25T12:00:00Z" }';  
var dates = JSON.parse(jsontext, dateReviver);  
document.write(dates.birthdate.toUTCString());  
  
function dateReviver(key, value) {  
    var a;  
    if (typeof value === 'string') {  
        a = /^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2}(?:\.\d*)?)Z$/.exec(value);  
        if (a) {  
            return new Date(Date.UTC(+a[1], +a[2] - 1, +a[3], +a[4],  
                            +a[5], +a[6]));  
        }  
    }  
    return value;  
};  
  
// Output:  
// Thu, 25 Dec 2008 12:00:00 UTC  
  

Requirements

[!INCLUDEjsv58]

See Also

JSON.stringify Function
toJSON Method (Date)
Hub template sample app (Windows Store)