JavaScript: Check whether the provided argument is a valid JSON

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

Check Valid JSON

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

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

Sample Solution:

JavaScript Code:

// Define a function 'isValidJSON' that checks if a given string 'obj' is a valid JSON
const isValidJSON = obj => {
  // Try to parse the string as JSON
  try {
    JSON.parse(obj);
    // If parsing succeeds, return true
    return true;
  } catch (e) {
    // If parsing fails (due to invalid JSON), return false
    return false;
  }
};

// Test cases to check if the provided strings are valid JSON or not
console.log(isValidJSON('{"name":"Adam","age":20}')); // true (valid JSON)
console.log(isValidJSON('{"name":"Adam",age:"20"}')); // false (invalid JSON)
console.log(isValidJSON(null)); // false (not a string)

Output:

true
false
true

Flowchart:

Live Demo:

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

For more Practice: Solve these Related Problems:

• Write a JavaScript program that tests whether a given string is valid JSON using try/catch and JSON.parse().
• Write a JavaScript function that returns a boolean indicating if an input string can be successfully parsed as JSON.
• Write a JavaScript program that validates a JSON string and logs detailed error messages if parsing fails.
• Write a JavaScript function that checks for proper JSON structure and returns either the parsed object or an error flag.

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