邏輯或賦值 (||=)

const a = { duration: 50, title: "" };

a.duration ||= 10;
console.log(a.duration);
// Expected output: 50

a.title ||= "title is empty.";
console.log(a.title);
// Expected output: "title is empty."

x ||= y

const x = 1;
x ||= 2;

const x = {
  get value() {
    return 1;
  },
  set value(v) {
    console.log("Setter called");
  },
};

x.value ||= 2;

const x = 1;
x ||= console.log("y evaluated");
// Logs nothing

document.getElementById("lyrics").textContent ||= "No lyrics.";