Sometimes, we want to check if a string is JSON in JavaScript.
In this article, we’ll look at how to check if a string is JSON in JavaScript.
Check if a String is JSON in JavaScript
To check if a string is JSON in JavaScript, we can use the JSON.parse method within a try-catch block.
For instance, we can write:
const jsonStr = JSON.stringify({
foo: 'bar'
})
try {
const json = JSON.parse(jsonStr);
} catch (e) {
console.log('invalid json');
}
to check if jsonStr is a valid JSON string.
Since we created the JSON string by calling JSON.stringify with an object, it should be valid JSON.
Next, we have a try-catch block with the JSON.parse call in the try block to try to parse the jsonStr string with JSON.parse .
Since jsonStr is a valid JSON string, the code in the catch block shouldn’t run.
If jsonStr isn’t a valid JSON string, then the code in the catch block runs since JSON.parse will throw an exception if it’s called with an invalid JSON string.
Conclusion
To check if a string is JSON in JavaScript, we can use the JSON.parse method within a try-catch block.
