Getting error when push data in array and add it in repeater.

I want to push data in array and display it in repeater. But when i push data and display. It shows this error “Wix code SDK error: Each item in the items array must have a member named _id which contains a unique value identifying the item.” But i already added ‘_id’.
The code is like this.

let x = [{“_id”:“kjhkjhkj”, “dateeeee”: “22/72/417”},
{“_id”:“454sdfsd”, “dateeeee”: “23/72/417”},];

export function datePicker1_change(event) {
//Add your code for this event here:
let date = $w(‘#datePicker1’).value.getUTCDate()+1;
let month = $w(‘#datePicker1’).value.getMonth()+1;
let fullyear = $w(‘#datePicker1’).value.getFullYear();
let finaldate = date+‘-’+month+‘-’+fullyear;
let a = String(“{"_id":"jhg451", "dateeeee": "22/72/417"}”);
x.push(a);
console.log(x);
$w(“#daterepeater”).onItemReady( ($item, itemData, index) => {
let dateee = $item(“#date”);
dateee.text = itemData.dateeeee;
} );
$w(‘#daterepeater’).data = x;

}
Please help me to solve this issue…