How to insert the value-based if-condition in an array of objects [duplicate]

How can I insert the values in array of objects based on one value condition?

opayloadchild = [];

for (let i = 0; i < j; i++) {

     opayloadchild.push({
                            "A": "123456",
                            "B": data[i].x,
                            "C": data[i].y,
                            "D": data[i].z.toUpperCase(),
                            "E": data[i].d.toUpperCase(),
                            "F": data[i].e.toUpperCase()
                        })

}

In the above code I want to check inside the for-loop like if data[i].x is null or not.

If data[i].x = null then insert "" else the value.

How can I achieved this?