如何使用javascript在对象数组中执行计算

Question

I am performing calculation in nested object array in javascript. I have two inputs as shown

for the obj if obj.rate > mr then

cr = (((obj.amount * obj.rate) - (obj.amount * mr))/(obj.amount * obj.rate))*100 + "%", totalcost = (obj.netfee-(cr*amountwithfee)

if obj.rate < mr then

cr = (((obj.amount * mr) - (obj.amount * obj.rate))/(obj.amount * mr))*100 + "%", totalcost = (obj.netfee+(cr*amountwithfee)

How to do the above calculation in below function in precise manner

  var result = obj.forEach(e=>{
     ..obj,
     netfee: obj.fee + obj.payfee,
     amountwithfee: obj.amount-obj.netfee,
     cr: (((obj.amount * mr) - (obj.amount * obj.rate))/(obj.amount * mr))*100 + "%",
     totalcost: (obj.netfee+(cr*amountwithfee); 
  })
 console.log(result);

Inputs

  var mr = 0.5;
  var obj =[{
    amount: 1000,
    fee: 5,
    payfee:2,
    rate:0.49
  }]

Expected output:

  result = [{
    amount: 1000,
    fee: 5,
    payfee: 2,
    netfee: 7, 
    amountwithfee: 993,
    rate: 0.49,
    cr : -2%, 
    totalcost: 26.86
  }]

Answer 1

 //initiallizing var mr = 0.5; var obj =[ { amount: 1000, fee: 5, payfee:2, rate:0.49 }, { amount: 1000, fee: 5, payfee:2, rate:0.5 } ]; var result = []; //start calculation obj.forEach(x => { let netfee = 0; let amountwithfee = 0; let cr = 0; let totalcost = 0; netfee = x.fee + x.payfee; amountwithfee = x.amount- netfee; //write your login if (x.rate < mr) { cr = (((x.amount * mr) - (x.amount * x.rate))/(x.amount * mr))*100; totalcost = (netfee + (cr * amountwithfee)); } else { cr = (((x.amount * x.rate) - (x.amount * mr))/(x.amount * x.rate))*100; totalcost = (netfee - (cr * amountwithfee)); } //generate output result.push({ 'amount': x.amount, 'fee': x.fee, 'payfee': x.payfee, 'netfee': netfee, 'amountwithfee': amountwithfee, 'rate': x.rate, 'cr': cr + "%", 'totalcost': totalcost }); }); console.log(result); 

Answer 2

在进行数学计算时，在任何需要的地方使用parseInt()和parseFloat() ，或者使用eval()进行操作。