just write a regular replace replacement, right? Your data is not embedded deeply,

let arr = JSON.parse (data)
arr = arr.map (e = > {.e, id: e.id =''?'-': e.id})

can be replaced when displayed on the page, and there is no need to change the array. If you have to change the array, you can do this:

arr.forEach(v=>{  
    if(v.id == "") {
        v.id = "-";
    }  
});