using index of on array of objects

arr = [{x: "a", y: 1}, {x: "something", y: 2}]
arr.findIndex(obj => obj.x === "a" && obj.y === 1);        
            
        
     let ranks = [1, 5, 7, 8, 10, 7];
let index = ranks.findIndex(rank => rank === 7);
console.log(index);