Novice ask json array how to insert new fields and values?

{gid:"1",is_top:"0",title:"iphone"}
{gid:"2",is_top:"0",title:"iphone"}
{gid:"3",is_top:"0",title:"iphone"}
{gid:"4",is_top:"0",title:"iphone"}

such a structure, for example, add a field called is_vip, the value is 0, how to insert each item in js (WeChat Mini Programs)?
Thank you for your advice

Jun.29,2021

arr.forEach(item => {
item.is_vip = 0
})
Menu