// IIFE Goal: Create a new scope, return the data just once. All of data inside IIFE will be private as it would inside the fn scope.
// Using this way, we don't need to call it separately. And it ensures its called only once.
// IIFE is created only once, goal is 'NOT TO REUSE' by executing it multiple times.
// Result of running an IIFE is stored, or else it will disappear simply.
const ShoppingCart2 = (function(){
const cart = [];
const shippingCost = 10;
const totalPrice = 237;
const totalQuantity = 10;
const addToCart = function(product, quantity){
cart.push({product, quantity});
console.log(`${quantity} ${product} added to cart. Shipping cost is ${shippingCost}`);
};
const orderStock = function(product, quantity){
console.log(`${quantity} ${product} ordered from supplier`);
};
// Need to return something, in order to return a public API. For that, an object is returned containing stuff which needs to be made public.
return {
addToCart,
cart,
totalPrice,
totalQuantity
};
})();
// Everything inside the above module is private to the module.
// The above fn returns the object mentioned inside return statement and assign it to the ShoppingCart2 variable mentioned at the start of fn. This IIFE is returned then long ago.
// All this is possible because of closures. Hence, addToCart can acccess the cart variable.
ShoppingCart2.addToCart('apple', 4);
ShoppingCart2.addToCart('pizza', 5);
ShoppingCart2;
ShoppingCart2.shippingCost; // inaccessible.
缺點：
除了原生的 ES6 模組和模組模式之外，JS 還支援其他非 JS 原生的模組系統。前任。 AMD、CommonJS
前任。 Node.js 中自始至終都使用 CommonJS 模組。最近 ES6 模組已經在 Node.js 中實作
npm 儲存庫上的所有模組仍然使用 commonJS 模組系統，因為 npm 最初是為 Node 設計的。直到後來，npm 才成為整個 JS 世界的儲存庫。因此，我們基本上只能使用 CommonJS。所以，CommonJS 在 Node.js 中的影響還是需要被注意
就像 ES6 模組一樣，CommonJS 中 1 個檔案就是 1 個模組。
commonJS 程式碼在瀏覽器中不起作用，但在 Node.js 中可以
ES Modules 最終將取代所有模組系統，但目前我們還需要使用 commonjs。
export 關鍵字是一個對象，它沒有在我們的程式碼中以及瀏覽器中定義。
// EXPORT
export.addToCart = function(product, quantity){
cart.push({product, quantity});
console.log(`${quantity} ${product} added to cart. Shipping cost is ${shippingCost}`);
};
// IMPORT: is similar to ES Modules but would use a require fn.
// require is not defined in browser env but its defined in node env as its a part of commonjs
const addToCart = require('./shoppingCart.js')
以上是模組的詳細內容。更多資訊請關注PHP中文網其他相關文章！
