模块模式是否需要使用 IIFE？

Question

在 Udacity 课程中，它说了关于模块模式的矛盾内容：

The Module Pattern requires the use of IIFE's

和

At its core, the Module Pattern leverages scope, closures, and (commonly) IIFE's.

所以，如果我理解正确的话，模块模式需要使用闭包，但是闭包是否需要在 IIFE 中？

Answer 1

在 JavaScript ECMAScript 5 及更早版本中，an IIFE, or immediately-invoked function expression, was necessary to create a function scope that prevented var 声明在实现显示模块模式时会污染全局命名空间。

(function () {
  var foo = 'bar'
  var counter = 0

  this.someGlobalModule = function () {
    counter++

    return { foo: foo, counter: counter }
  }
}.call(this))
// this === window at top-level in browser

// no access to function-scope foo or counter, only someGlobalModule()
var value = someGlobalModule()

// value.foo === 'bar'
// value.counter === 1

现在使用 JavaScript ECMAScript 6，引入 const and let declarations allow block-scope variables, as opposed to function-scope, so you can simply use a block-scope 来实现显示模块模式：

{
  const foo = 'bar'
  let counter = 0

  // this === window at top-level in browser
  this.someGlobalModule = () => {
    counter++

    return { foo, counter }
  }
}

// no access to block-scope foo or counter, only someGlobalModule()
let value = someGlobalModule()

// value.foo === 'bar'
// value.counter === 1

模块模式是否需要使用 IIFE？

Does the module pattern require the use of an IIFE?

javascript

iife