check if the column value in object A (i.e., "paymentsType") exists as a key in the first element of leArray[0]. If the key exists, you want to override the value in leArray[0] with the value from object A.

// Define the input objects
let objectA = {
    "value": "test 1333",
    "column": "paymentsTypeNew",
    "id": "xyz123"
};

let leArray = [
    { 
        "accountType": "477777",
        "activityType": "7888888",
        "paymentsType": "3445555paymentsType",
        "rowId": "abcd" 
    },
    { 
        "accountType": "477777",
        "activityType": "7888888",
        "paymentsType": "3445555paymentsType",
        "rowId": "12345"  
    },
    { 
        "accountType": "477777",
        "activityType": "7888888",
        "paymentsType": "jahapanna",
        "rowId": "xyz123"  
    }
];

// Find the object in leArray where rowId matches the id in objectA
let matchingObject = leArray.find(item => item.rowId === objectA.id);

if (matchingObject) {
    // Check if the column in objectA exists as a key in the matching object
    if (matchingObject.hasOwnProperty(objectA.column)) {
        // If the key exists, override the value
        matchingObject[objectA.column] = objectA.value;
    } else {
        // If the key doesn't exist, add the new key-value pair
        matchingObject[objectA.column] = objectA.value;
    }
}

// Output the updated leArray for confirmation
console.log(leArray);