數組包含空值存儲在空值的其他一些部分

Question

var dataList = [ 
                 { date: '2019-08-08', class: null, users: 21 },
                 { date: '2019-08-08', class: 'lower', users: 21 },  
                 { date: '2019-08-08', class: 'upper', users: 3}
                 { date: '2019-08-08', class: 'middle', users: 5}

               ];

如果數組鍵包含null我想要這個我想像這樣存儲我在數組中有多個日期並且每個數組都包含一個空值

store null into "Others" key 
var dataList = [ 
                { date: '2019-08-08', class: 'Others', users: 21 },
                { date: '2019-08-08', class: 'lower', users: 21 },  
                { date: '2019-08-08', class: 'upper', users: 3}
                { date: '2019-08-08', class: 'middle', users: 5}
              ];

Answer 1

使用forEach循環

 var dataList = [ { date: '2019-08-08', class: null, users: 21 }, { date: '2019-08-08', class: 'lower', users: 21 }, { date: '2019-08-08', class: 'upper', users: 3}, { date: '2019-08-08', class: 'middle', users: 5} ]; dataList.forEach(function(e){ if(e.date==null) e.date='Others' if(e.class==null) e.class='Others' if(e.users==null) e.users='Others' }) console.log(dataList)

Answer 2

像這樣使用map ：

 var dataList = [ { date: '2019-08-08', class: null, users: 21 }, { date: '2019-08-08', class: 'lower', users: 21 }, { date: '2019-08-08', class: 'upper', users: 3}, { date: '2019-08-08', class: 'middle', users: 5} ]; const res = dataList.map(({ class: c, ...r }) => ({ class: c == null ? "Other" : c, ...r })); console.log(res);

Answer 3

使用array.map() ：

map() 方法使用對調用數組中的每個元素調用提供的函數的結果創建一個新數組。

 var dataList = [ { date: '2019-08-08', class: null, users: 21 }, { date: '2019-08-08', class: 'lower', users: 21 }, { date: '2019-08-08', class: 'upper', users: 3}, { date: '2019-08-08', class: 'middle', users: 5} ]; let newList = dataList.map( (obj) => obj.class == null? { ...obj, class: "Other" } : obj );

如果您需要檢查 obj 中的任何鍵，而不僅僅是class鍵 - 在這里評論，我將編輯我的答案。

Answer 4

這是非常簡單的代碼如下

dataList=dataList.map(x=>{x.class=x.class||"Others";return x})

 var dataList = [ { date: '2019-08-08', class: null, users: 21 }, { date: '2019-08-08', class: 'lower', users: 21 }, { date: '2019-08-08', class: 'upper', users: 3}, { date: '2019-08-08', class: 'middle', users: 5} ]; dataList=dataList.map(x=>{x.class=x.class||"Others";return x}) console.log(dataList)