You can implement custom behaviors for operators and methods using Symbols. For example, you can use the Symbol.toPrimitive well-known symbol to define how an object should be converted to a primitive value

coercionProtection

const obj = {
  [Symbol.toPrimitive]: function (hint) {
    if (hint === "number") {
      return 42;
    } else if (hint === "string") {
      return "Hello";
    } else {
      return true;
    }
  },
};
console.log(+obj); // 42
console.log(`${obj}`); // "Hello"
console.log(obj === true); // false
console.log(obj[Symbol.toPrimitive]()); // true;