JSON-parse-Transformed.html - JSON.parse() Value Transformed

Q

How to write a reviver function to transform values while the JSON.parse() function is parsing the JSON text string?

✍: FYIcenter.com

A

Below is a good example on using a reviver function with the JSON.parse() call to transform parsed JSON element values:

<!-- JSON-parse-Transformed.html
     Copyright (c) FYIcenter.com
-->
<html>
<body>
<script type="text/javascript">

function transformer(key, value) {
    if (key == "age") {
       return undefined;
    } else if (key == "group" && value==null) {
       return "Guest";
    } else {
       return value;
    }
}

function parser(str) {
   document.write("\njson = "+str+"\n");
   var obj = JSON.parse(str,transformer);
   for (var prop in obj) {
       document.write(`obj.${prop} = ${obj[prop]}\n`);
   }
}

   document.write("<p>JSON.parse() Reviver to Transform Values:</p>");
   document.write("<pre>");

   parser('{"name": "Joe", "age": 25, "group": null}');
   parser('{"name": "Jay", "age": 55, "group": "VIP"}');
   parser('{"name": "Kim", "age": 30, "group": "Host"}');

   document.write("</pre>");
</script>
</body>
</html>

The transformer() is used as the reviver function in the JSON.parse() call to remove the "age" name value pairs, and to provide a default value "Guest" to the "group" name value pairs.

Open the above code in a Web browser. You see the following output:

JSON.parse() Reviver to Transform Values:

json = {"name": "Joe", "age": 25, "group": null}
obj.name = Joe
obj.group = Guest

json = {"name": "Jay", "age": 55, "group": "VIP"}
obj.name = Jay
obj.group = VIP

json = {"name": "Kim", "age": 30, "group": "Host"}
obj.name = Kim
obj.group = Host

⇒ JSON.stringify() Function in JavaScript

⇐ Call JSON.parse() with Reviver Function

⇑ Using JSON in JavaScript

⇑⇑ JSON Tutorials

2017-09-08, ∼3003🔥, 0💬

JSON-stringify.html - JSON.stringify() Example Code
Where to get a JSON.stringify() Example Code in JavaScript? Here is a good JSON.stringify() example code in JavaScript.  <html> <body> <script type="text/javascript"> var str1 = JSON.strin... 2021-08-04, ∼4403🔥, 1💬

Call JSON.stringify() with Replacer Function
What is a replacer function that you can provide the JSON.stringify() function call? The replacer function is an event handler function that is called repeatedly whenever a value, an array element or an object property is stringified during the execution of the JSON.stringify() function. The replace... 2017-09-08, ∼3595🔥, 0💬

JSON-parse-Transformed.html - JSON.parse() Value Transformed
How to write a reviver function to transform values while the JSON.parse() function is parsing the JSON text string? Below is a good example on using a reviver function with the JSON.parse() call to transform parsed JSON element values: <!-- JSON-parse-Transformed.html Copyright (c) FYIcenter... 2017-09-08, ∼3004🔥, 0💬

JSON-stringify-Object.html - JSON.stringify() on Objects
How JSON.stringify() behaves on JavaScript objects? When processing an object, JSON.stringify() behave depending on the type of objects based on the following rules: Boolean, Number, and String objects are converted to the corresponding primitive JSON values during stringification. Date objects are ... 2017-09-08, ∼2922🔥, 0💬

Call JSON.parse() with Reviver Function
What is a reviver function that you can provide the JSON.parse() function call? The reviver function is an event handler function that is called repeatedly whenever a JSON element is parsed during the execution of the JSON.parse() function. The reviver function must defined with the following signat... 2023-09-07, ∼2465🔥, 0💬

JSON-parse-Error.html - JSON.parse() Errors
How to catch errors when calling the JSON.parse() function in JavaScript? If you want to catch errors when calling the JSON.parse() function in JavaScript, you can follow this tutorial: 1. Use the "try {...} catch {...}" block to catch the error object throw from the JSON.parse() function, as shown ... 2023-09-07, ∼2399🔥, 0💬

JSON.parse() Function in JavaScript
Where to get the detailed description of the JSON.parse() Function in JavaScript? Here is the detailed description of the JSON.parse() Function in JavaScript. Description - The JSON.parse() function parses a JSON string, constructing the JavaScript value or object described by the string. An optiona... 2023-04-13, ∼2296🔥, 0💬

What Is JavaScript JSON Object
What Is JavaScript JSON Object? The JSON object is a built-in object in the JavaScript engine that offers 2 functions to parse and generate JSON text strings: 1. JSON.parse() - Parses a text string from a JSON text string, constructs the JavaScript value. An optional reviver function can be provided... 2023-04-13, ∼2128🔥, 0💬

JSON-parse.html - JSON.parse() Example Code
Where to get a JSON.parse() Example Code in JavaScript? Here is a good JSON.parse() example code in JavaScript.  <html> <body> <script type="text/javascript"> var val1 = JSON.parse('2020'); //... 2023-04-13, ∼1998🔥, 0💬

All rights in the contents of this web site are reserved by the individual author. fyicenter.com does not guarantee the truthfulness, accuracy, or reliability of any contents.