JavaScript 几种循环方式以及模块化的总结

for (var index = 0; index < myArray.length; index++) {
 console.log(myArray[index]);
}

myArray.forEach(function (value) {
 console.log(value);
});

var obj = {a:1, b:2, c:3};

for (var prop in obj) {
 console.log("obj." + prop + " = " + obj[prop]);
}

// 输出:
// "obj.a = 1"
// "obj.b = 2"
// "obj.c = 3"

for (var index in myArray) {  // 不推荐这样
 console.log(myArray[index]);
}

let iterable = [10, 20, 30];

for (let value of iterable) {
 console.log(value);
}
// 10
// 20
// 30

let iterable = "boo";

for (let value of iterable) {
 console.log(value);
}
// "b"
// "o"
// "o"

let iterable = new Map([["a", 1], ["b", 2], ["c", 3]]);

for (let [key, value] of iterable) {
 console.log(value);
}
// 1
// 2
// 3

for (let entry of iterable) {
 console.log(entry);
}
// [a, 1]
// [b, 2]
// [c, 3]

let iterable = new Set([1, 1, 2, 2, 3, 3]);

for (let value of iterable) {
 console.log(value);
}
// 1
// 2
// 3

/-----export [test.js]-----/
let myName = "Tom";
let myAge = 20;
let myfn = function(){
  return "My name is" + myName + "! I'm '" + myAge + "years old."
}
let myClass = class myClass {
  static a = "yeah!";
}
export { myName, myAge, myfn, myClass }

/-----import [xxx.js]-----/
import { myName, myAge, myfn, myClass } from "./test.js";
console.log(myfn());// My name is Tom! I'm 20 years old.
console.log(myAge);// 20
console.log(myName);// Tom
console.log(myClass.a );// yeah!

console.log(myfn());// My name is Tom! I'm 20 years old.
console.log(myAge);// 20
console.log(myName);// Tom
console.log(myClass.a );// yeah!

import { myName as name1 } from "./test1.js";
import { myName as name2 } from "./test2.js";
console.log(name1);// Tom
console.log(name2);// Jerry