const a = {x:1};
console.log({...a}.x);
// 1
console.log(window.Math);
// Math {abs: ƒ, acos: ƒ, acosh: ƒ, asin: ƒ, asinh: ƒ, …}
console.log({...window}.Math);
// undefinedI don't understand why {...a}.x evaluates 1, but {...window}.Math evaluates undefined.