new操作符具體幹了什麼？（4個步驟）

原創 apple_2021 2020-07-03 08:18

一般要創建實例的時候，都要var obj = new 構造函數

new操作符在這裏主要做了四步

  • 創建一個空對象obj
  • 設置原型鏈 即 obj . _proto _ = 構造函數.prototype ;
  • 讓構造函數中的this指向obj
  • 返回對象obj
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