【筆記】Object.values、Object.entries與Object.fromEntries

Object.values()：以數組形式返回給定對象可枚舉屬性的值，如：[ 值1，值2，值3，值4 ]

舉例如下：

	  //對象
      let obj1 = {one:'a',two:'b',three:'c'};
      Object.values(obj1);   // ["a", "b", "c"]

      //鍵爲數字的對象,注意：此時會按照數字鍵的順序輸出
      let obj2 = {1:'one',3:'tree',2:'two'};
      Object.values(obj2);   // ["one", "two", "tree"]

      //數組
      let obj3 = ['1','2','3'];
      Object.values(obj3);   // ["1", "2", "3"]

      //字符串
      Object.values('abcd');   // ["a", "b", "c", "d"]

Object.values()：以數組形式返回給定對象可枚舉屬性的 [鍵:值]，如：[ [鍵1，值1]，[鍵2，值2]，[鍵3，值3]，[鍵4，值4] ]

Object.fromEntries()：對Object.values()反向操作，將 [ [鍵1，值1]，[鍵2，值2]，[鍵3，值3]，[鍵4，值4] ] 轉爲{鍵1：值1，鍵2：值2，鍵3：值3，鍵4：值4}

舉例如下：

      //對象
      let obj1 = {one:'a',two:'b',three:'c'};
      Object.entries(obj1);   // [["one", "a"],["two", "b"],["three", "c"]]
      //Object.fromEntries()對Object.entries()反向操作
      Object.fromEntries([["one", "a"],["two", "b"],["three", "c"]]);   //{one: "a", two: "b", three: "c"}

      //鍵爲數字的對象，注意：此時會按照數字鍵的順序輸出
      let obj2 = {1:'one',3:'tree',2:'two'};
      Object.entries(obj2);   //[["1", "one"],["2", "two"],["3", "tree"]]
      //Object.fromEntries()對Object.entries()反向操作
      Object.fromEntries([["1", "one"],["2", "two"],["3", "tree"]]);   //{1: "one", 2: "two", 3: "tree"}

      //數組，注意：此時將數組['1','2','3']當作含數字鍵的對象{0:'1',1:'2','2','3'}
      let obj3 = ['1','2','3'];
      Object.entries(obj3);   // [["0", "1"],["1", "2"],["2", "3"]]
      //Object.fromEntries()對Object.entries()反向操作
      Object.fromEntries([["0", "1"],["1", "2"],["2", "3"]]);   //{0: "1", 1: "2", 2: "3"}

      //字符串，同數組
      Object.entries('abcd');   // [["0", "a"],["1", "b"],["2", "c"],["3", "d"]]
      //Object.fromEntries()對Object.entries()反向操作
      Object.fromEntries([["0", "a"], ["1", "b"], ["2", "c"], ["3", "d"]]);   //{0: "a", 1: "b", 2: "c", 3: "d"}