javascript - 每月按金计息

我想每周/每两周/每月/每年复利。

我还希望有一个可以添加的存款金额的选项。

我已经尝试过计算最终产生的金额的标准公式，如下所示:

例如，这是我每周计算利息复利的方法:

function calculateWeekly(state: any) {
  const { savings, deposit ,interest, timePeriodSelector, timePeriodLength } = state;

  let numberOfYears = 0;

  if (timePeriodSelector === "weekly") {
    numberOfYears = timePeriodLength / weeksInAYear;
  } else if (timePeriodSelector === "fortnightly") {
    numberOfYears = (timePeriodLength / weeksInAYear) * 2;
  } else if (timePeriodSelector === "monthly") {
    numberOfYears = (timePeriodLength / weeksInAYear) * weeksInAMonth;
  } else if (timePeriodSelector === "annually") {
    numberOfYears = (timePeriodLength / weeksInAYear) * weeksInAYear;
  }

  const weeklyRate = interest / 100 / weeksInAYear;
  const lengthOfCompunding = numberOfYears * weeksInAYear;

  let startingFigure = parseInt(savings) + parseInt(deposit);

  //total gets added on for every time cycle of week
  let total =
    (startingFigure * (Math.pow(1 + weeklyRate, lengthOfCompunding) - 1)) / weeklyRate;

  return roundToTwoDP(total);
}

上面代码的问题是，每次产生利息时，都会将押金添加到计算中。因此，在10周内每周支付10美元的押金实际上会加起来为100美元。

我尝试了一种使用每周循环的方法来产生兴趣的方法，如下所示:

  // loops how many times to compound the interest
  for(let i = numberOfYears - (1/weeksInAYear); i > 0; i-= (1/weeksInAYear)){
    let interestGained = (total * (Math.pow((1 + weeklyRate), lengthOfCompunding))) - total;
    total += interestGained + savings;
  }

谢谢你的帮助!

最佳答案

这应该做您想要的:

const range = (min, max) => {

    const size = 1 + max - min

    return [...Array(size).keys()].map(n => n + min)
}

const weeksInAYear = 52

const addWeeklyInterest = interestRatePerWeek => (savings, _) => savings + savings * interestRatePerWeek

const calculateTotal = (savings, numberOfYears, interestRatePerWeek) => {

    const numberOfWeeks = numberOfYears * weeksInAYear

    return range(1, numberOfWeeks).reduce(addWeeklyInterest(interestRatePerWeek), savings)
}

console.log(calculateTotal(1000.00, 1, 0.02))

输出为2800.328185448178。您可能需要将其四舍五入以用于显示目的，但也要记住，如果准确性很重要，则不能使用浮点数。

关于javascript - 每月按金计息，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/57642627/