JavaScript:将表达式转换为字符串

var num = 10;
console.log(num.toString()); // 输出 "10"

var arr = [1, 2, 3];
console.log(arr.toString()); // 输出 "1,2,3"

var obj = {name: "John", age: 30};
console.log(obj.toString()); // 输出 "[object Object]"

var num = 10;
console.log(String(num)); // 输出 "10"

var bool = true;
console.log(String(bool)); // 输出 "true"

var arr = [1, 2, 3];
console.log(String(arr)); // 输出 "1,2,3"

var obj = {name: "John", age: 30};
console.log(String(obj)); // 输出 "[object Object]"

var num = 10;
console.log(`The number is ${num}`); // 输出 "The number is 10"

var name = "John";
console.log(`Hello, ${name}!`); // 输出 "Hello, John!"