是否有反向逻辑无效赋值？

问：

因此，仅当当前存储的值为空时，运算符才会将值分配给变量。??=

也许我错过了显而易见的东西，但我想不出一个巧妙的解决方案（没有 if 语句）仅在值不为空时才分配？

我正在使用 nodeJS 来提供更多上下文。

我想要

let x r??= 2;
// Updates 'x' to hold this new value
x r??= undefined;
// Has no effect, since the value to assign is nullish
console.log(x); // 2

编辑以更清楚地说明我的问题：

我只想为变量分配一个新值，如果该新值不为空。

let iceCream = {
    flavor: 'chocolate'
}

const foo = 2.5
const bar = undefined;

iceCream.price r??= bar
// does not assign the new value because it is nullish
console.log(iceCream.price) // expected to be error, no such property

iceCream.price r??= foo
// assigns the new value because it is not nullish but a float
console.log(iceCream.price) // expected to be 2.5

iceCream.price r??= bar
// does not assign the new value because it is nullish
console.log(iceCream.price) // expected to still be 2.5