JSFiddle - React, Tailwind, and code Playground

JavaScript

jsonString = {
    "1": {
        "product_id": "1",
        "product_model": "HFJ5G1.5",
        "product_type": "plat",
        "product_return": "graviteits"
    },
    "2": {
        "product_id": "2",
        "product_model": "HHJ5S2.5",
        "product_type": "holle plunjer",
        "product_return": "veer"
    }
};

var count = 0;

for (prop in jsonString) {
    if (jsonString.hasOwnProperty(prop)) {
        count++;
    }
}

alert(count);