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What is the best way to check if a string is valid JSON or not using JavaScript?


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Try to parse it and catch any failure. There isn’t a more fool-proof way to check if JSON is valid than that. Something like this would work:

function isValidJSON(s) { 
        try { 
                return true; 
        catch (e) { 
        return false; 
// Run a few test cases: 
console.log(`isValidJSON("4") = ${isValidJSON("4")}`); // prints true 
console.log(`isValidJSON("[4") = ${isValidJSON("[4")}`); // prints false 
console.log(`isValidJSON("[4]") = ${isValidJSON("[4]")}`); // prints true 


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