循环语句

/*
    for(...) {}
    for(... of ...) {}
    for(... in ...) {}
*/

let fruits = ['apple', 'blueberry', 'cherry', 'durian', 'Fig', 'Grape', 'Hwa', 'Kiwi', 'Lichee', 'Mango', 'Nucleus'];

let message = '';

for (let i = 1; i < fruits.length; i++) {
   message += `(${i}) ${fruits[i - 1]} `;
}

console.log(message); // (1) apple (2) blueberry (3) cherry (4) durian (5) Fig (6) Grape (7) Hwa (8) Kiwi (9) Lichee (10) Mango 

console.log('')

message = '';

for(let value of fruits) {
    message += `${value} `
}

console.log(message); // apple blueberry cherry durian Fig Grape Hwa Kiwi Lichee Mango Nucleus 

let product = { id: 5685, name: 'Tablet PC', color: 'Gold', Price: '1200', OS: 'Android' }

message = '';

for(let str in product) {
    message += `${str} `;
}

console.log(message); // id name color Price OS 

let a01 = [520, 530, 1314, 2013, 2014, 2591.8];

let sum = 0;

for (let num of a01) {
	sum += num;
	console.log(`current number = ${num}`)
}

/*
	current number = 520
	current number = 530
	current number = 1314
	current number = 2013
	current number = 2014
	current number = 2591.8
 */

console.log('')

let greeting = 'Hello, world, Solar System, Galaxy.';

for (let c of greeting) {
	console.log(c); // 遍历字符串的每一个字符
}

console.log('')

function display(...args) {
	for (let arg of args) {
		console.log(arg)
	}
	console.log('');
	for (let arg of arguments) {
		console.log(arg)
	}
}

display('what', 'when', 'where', 'which', 'who')

// 生成器函数
function* gen01() {
	let top_value = parseInt(30 * Math.random());
	for (let i = 1; i < top_value; i += 3) {
		yield i; // 遇到 yield，函数将暂时终止； yield 有 return 的功能，向外返回值
	}
}

let gen02 = {
	*[Symbol.iterator]() {
		let top_value = parseInt(30 * Math.random());
		for (let i = 1; i < top_value; i += 3) {
			yield i;
		}
	}
}

for (let num of gen01()) {
	console.log(num)
}

console.log('')

for (let num of gen02) {
	console.log(num)
}

let number_array = [...gen01()];
console.log(number_array); // [1, 4, 7, 10, 13, 16, 19]

console.log('')

class Planets {
	* solar_system() {
		let planet_list = ['水星', '金星', '地球', '火星', '木星', '土星', '天王星'];
		for(let planet of planet_list) {
			yield planet;
		}
	}
}

p01 = new Planets();

let a_copy = [...p01.solar_system()];

console.log(a_copy); // ["水星", "金星", "地球", "火星", "木星", "土星", "天王星"]

/*
    while(...) {
        ...  
    }

    do {
        ...
    } while(...) { ... }
*/

let fruits = ['apple', 'blueberry', 'cherry', 'durian', 'Fig', 'Grape', 'Haw', 'Kiwi'];

let product = {
	id: 5685,
	name: 'Tablet PC',
	color: 'Gold',
	Price: '1200',
	OS: 'Android'
};

let message = '', count = 1;

while(count < fruits.length + 1) {
	message += `(${count}) ${fruits[count - 1]} `;
	count++;
}

console.log(message); // (1) apple (2) blueberry (3) cherry (4) durian (5) Fig (6) Grape (7) Haw (8) Kiwi 
console.log('');

message = '', count = 1;

do {
	message += `(${count}) ${fruits[count-1]} `;
	count ++;
} while(count < fruits.length + 1);

console.log(message); // (1) apple (2) blueberry (3) cherry (4) durian (5) Fig (6) Grape (7) Haw (8) Kiwi