javascript - Angular JS : How to stop sum of complex filed values crossing a limit?

Question

我有一个对象数组，其中每个对象都有一个百分比值。用户可以输入任何值。如何将百分比值的总和限制为 100？例如:

[ {"name":"Pradeesh","contribution":4534,"percentage":40}, {"name":"Kumar","contribution":3425,"percentage":30}, {"name":"Rajesh","contribution":1234,"percentage":20}, {"name":"Romeo","contribution":3434,"percentage":10}]

在这种情况下，如果任何人尝试更改任何用户的百分比值，它应该抛出一个错误，指出总数超过 100。

Answer 1

考虑到您的对象数组是 myObject，您可以在该对象上添加一个观察者并检查总百分比是否超过 100

$scope.$watch(function(){return myObject;},function (newValue,oldValue) {
    var totalPercentage = 0;
    newValue.forEach(function(value){
        totalPercentage += value.percentage;
    });
    if(totalPercentage > 100){
        myObject = oldValue;
        throw "Total Percentage Exceeds 100"; 
    }
},true);