对象类型转换Javascript

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: 25};
console.log(obj.toString()); // 输出 "[object Object]"

var str = "10";
console.log(parseInt(str)); // 输出 10

var floatStr = "3.14";
console.log(parseFloat(floatStr)); // 输出 3.14

var obj = {name: "John", age: 25};
console.log(JSON.stringify(obj)); // 输出 '{"name":"John","age":25}'

var num = 0;
console.log(Boolean(num)); // 输出 false

var str = "";
console.log(Boolean(str)); // 输出 false

var obj = {};
console.log(Boolean(obj)); // 输出 true