在json对象javascript下划线中添加具有另一个属性的百分比值的属性

Question

My base data

[{
        month: 'Jan',
        cat: 'A',
        val: 20
    },{
        month: 'Jan',
        cat: 'B','
        val: 5
    },{
        month: 'Jan',
        cat: 'C',
        val: 10
    },{
        month: 'Feb',
        cat: 'A',
        val: 30
    },{
        month: 'Feb',
        cat: 'B',
        val: 10
    },{
        month: 'Feb',
        cat: 'C',
        val: 20
    }];

I would like to add another property called 'percent' to above object and its value would be the percent of property 'val'

Any help is sincerely appreciated..

Answer 1

Calculate the total using Array#reduce method and then add percentage field using Array#forEach method.

 var data = [{ month: 'Jan', cat: 'A', val: 20 }, { month: 'Jan', cat: 'B', val: 5 }, { month: 'Jan', cat: 'C', val: 10 }, { month: 'Feb', cat: 'A', val: 30 }, { month: 'Feb', cat: 'B', val: 10 }, { month: 'Feb', cat: 'C', val: 20 }]; var total = data.reduce(function(a, b) { return a + b.val }, 0); data.forEach(function(v) { v.percentage = (v.val * 100 / total).toFixed(2) }); console.log(data);