JSFiddle - React, Tailwind, and code Playground
JavaScript
var criteria = '{propertyType: "{"propertyType1":"Apartment Style Flat","propertyType2":"Loft Style"}", houseAge: "", living_area: ""}';
$.each($.parseJSON(criteria), function(i, v) {
console.log("i " + i + " v " + v);
})(jQuery);
/*
VM2015:1 Uncaught SyntaxError: Unexpected token p in JSON at position 19
*/