const string = "99";
// 隱式轉(zhuǎn)換
console.log(string * 1 + 77);
// 顯式轉(zhuǎn)換
console.log(Number(string) + 77);

const number = 66;
console.log(typeof number);
// 隱式轉(zhuǎn)換
console.log(typeof (number + ""));
// 顯式轉(zhuǎn)換
console.log(typeof String(number));

const string = "66.66alison";
console.log(parseInt(string));
console.log(parseFloat(string));

const name = "alison";
console.log(name.split(""));

const array = ["yooo", "alison", "ruby", "andy"];
console.log(array.join(""));
console.log(array.join("&"));

console.log(Number([]));
console.log(Number([3]));
console.log(Number([1, 2, 3]));

const array = ["yooo", "alison", "ruby", "andy"];
console.log(array.toString());
const number = 99;
console.log(typeof number.toString());

let number = 99;
console.log(number == true);

let hd = '0';
let hd2 = "1";
let hd3 = "99";
console.log(hd == false);
console.log(hd2 == true);
console.log(hd3 == true);

let number = 99;
if (number) console.log("number");

console.log(Boolean([]));
console.log(Boolean({}));

// 數(shù)值
let number = 0;
number = !!number;
console.log(Boolean(number));
// 字符串
let string = "Alison";
console.log(!!string);
console.log(Boolean(string));
// 數(shù)組
let array = [];
console.log(!!array);
console.log(Boolean(array));
// 對(duì)象
let object = {};
console.log(!!object);
console.log(Boolean(object));
// 日期
let date = new Date();
console.log(!!date);
console.log(Boolean(date));