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JavaScript: Check whether the provided argument is a valid JSON

JavaScript fundamental (ES6 Syntax): Exercise-183 with Solution

Write a JavaScript program to check whether the provided argument is a valid JSON.

  • Use JSON.parse() and a try... catch block to check if the provided string is a valid JSON.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
const isValidJSON = obj => {
  try {
    JSON.parse(obj);
    return true;
  } catch (e) {
    return false;
  }
};
console.log(isValidJSON('{"name":"Adam","age":20}'));
console.log(isValidJSON('{"name":"Adam",age:"20"}'));
console.log(isValidJSON(null));

Sample Output:

true
false
true

Flowchart:

flowchart: Check whether the provided argument is a valid JSON

Live Demo:

See the Pen javascript-basic-exercise-183-1 by w3resource (@w3resource) on CodePen.


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JavaScript: Tips of the Day

How to check whether a string contains a substring in JavaScript?

ECMAScript 6 introduced String.prototype.includes:

const string = "foo";
const substring = "oo";

console.log(string.includes(substring));

includes doesn't have Internet Explorer support, though. In ECMAScript 5 or older environments, use String.prototype.indexOf, which returns -1 when a substring cannot be found:

var string = "foo";
var substring = "oo";

console.log(string.indexOf(substring) !== -1);

Ref: https://bit.ly/3fFFgZv