Вы можете использовать JSON .stringify и заменить:
const json = {
id: "1",
employee_name: "Tiger Nixon",
employee_salary: "320800",
employee_age: "61",
profile_image: ""
};
document.getElementById("app").innerHTML = JSON.stringify(json, (key, value) => (value || ''), 4).replace(/"([^"]+)":/g, '$1:');
const json = {
id: "1",
employee_name: "Tiger Nixon",
employee_salary: "320800",
employee_age: "61",
profile_image: ""
};
document.getElementById("app").innerHTML = JSON.stringify(json, (key, value) => (value || ''), 4).replace(/"([^"]+)":/g, '$1:');
<div id="app"></div>