How to check if the response of a fetch is a json object in javascript

Question

I\'m using fetch polyfill to retrieve a JSON or text from a URL, I want to know how can I check if the response is a JSON object or is it only text

fetch(UR         


        

Answer 1

Use a JSON parser like JSON.parse:

function IsJsonString(str) {
    try {
        var obj = JSON.parse(str);

         // More strict checking     
         // if (obj && typeof obj === "object") {
         //    return true;
         // }

    } catch (e) {
        return false;
    }
    return true;
}