AngularJS-如何檢查特定鍵在數組中是否具有特定值

Question

在Angular中，我有一個像這樣的數組：

$scope.colors =["blue","red","pink","yellow"];

還有另一個對象

$scope.cars=[{"brand":"Ford","color":"blue"},{"brand":"Ferrari","color":"red"},{"brand":"Rolls","color":"blue"}];

我想做過濾器，這樣

<ul>
    <li ng-repeat="n in colors | filter:colorFilter">
    </li>
</ul>

在NG-重復只會顯示在元素$scope.colors ，由於價值觀的存在$scope.cars

換句話說，它只會顯示藍色和紅色

提前致謝！

Answer 1

您可以使用map方法，該方法接受回調函數作為參數，以便從$scope.cars每個汽車項目中獲取所有顏色，然后使用Set構造函數以查找unique顏色。 然后，您必須使用filter功能。

然后，您必須使用filter功能。

 let colors =["blue","red","pink","yellow"]; let cars = [{"brand":"Ford","color":"blue"},{"brand":"Ferrari","color":"red"},{"brand":"Rolls","color":"blue"}]; let uniqueColours= [...new Set(cars.map(c => c.color))]; const filteredColors = colors.filter(a=>uniqueColours.includes(a)); console.log(filteredColors); 

您可以單行執行此操作：

 const colors =["blue","red","pink","yellow"],cars = [{"brand":"Ford","color":"blue"},{"brand":"Ferrari","color":"red"},{"brand":"Rolls","color":"blue"}], filteredColors = colors.filter(a => cars.map(a => a.color).includes(a)); console.log(filteredColors); 

沒有箭頭功能。

 const colors =["blue","red","pink","yellow"],cars = [{"brand":"Ford","color":"blue"},{"brand":"Ferrari","color":"red"},{"brand":"Rolls","color":"blue"}], filteredColors = colors.filter(function(a){ return cars.map(function(c){ return c.color; }).includes(a)}); console.log(filteredColors); 

Answer 2

給定顏色和汽車陣列，您可以通過以下方式過濾顏色 ：

 var colors =["blue","red","pink","yellow"]; var cars=[ {"brand":"Ford","color":"blue"},{"brand":"Ferrari","color":"red"},{"brand":"Rolls","color":"blue"}]; var filteredColors = colors.filter(color => cars.some(car => car.color === color)); console.log(filteredColors); 

如果您不能使用ES6，則應為：

 var colors =["blue","red","pink","yellow"]; var cars=[ {"brand":"Ford","color":"blue"},{"brand":"Ferrari","color":"red"},{"brand":"Rolls","color":"blue"}]; var filteredColors = colors.filter(function(color) { return cars.some(function(car) { return car.color === color; }); }); console.log(filteredColors);