js 变成字符串

let num = 123;
let str = num.toString(); // "123"

let bool = true;
str = bool.toString(); // "true"

let num = 123;
let str = String(num); // "123"

let nul = null;
str = String(nul); // "null"

let undef = undefined;
str = String(undef); // "undefined"

let name = "Alice";
let age = 30;
let greeting = `Hello, my name is ${name} and I am ${age} years old.`; // "Hello, my name is Alice and I am 30 years old."

let firstName = "Alice";
let lastName = "Smith";
let fullName = firstName + " " + lastName; // "Alice Smith"

let nul = null;
console.log(nul.toString()); // TypeError: Cannot read properties of null (reading 'toString')

let undef = undefined;
console.log(undef.toString()); // TypeError: Cannot read properties of undefined (reading 'toString')

// 使用 String() 函数
console.log(String(nul)); // "null"
console.log(String(undef)); // "undefined"