javascript - 如何在循环中找到对象数组的总和？

我不确定根据我对问题的描述，我的问题的措词是否正确，因此请编辑它是否更准确。

我试图构建一个印花税计算器来改善我的JS，我有一系列对象使用不同的“带”和“百分比”，这些对象用于根据用户输入来计算税金。我已附上一张图片以更好地理解



我在表格中显示每个波段的税额，并且试图通过在“ TAX”列中查找所有值的总和来查找总税额。

当前，它只是显示最高值。

我已经尽力而为，但没有任何效果，我该如何解决？

这是我的代码，

 $(function (jQuery) {

     (function stampDutyCalculator() {

     var taxbands = [
         {
             min: 0,
             max: 125000,
             percent: 0
         },
         {
             min: 125000,
             max: 250000,
             percent: 0.02
         },
         {
             min: 250000,
             max: 925000,
             percent: 0.05
         },
         {
             min: 925000,
             max: 1500000,
             percent: 0.1
         },
         {
             min: 1500000,
             max: null,
             percent: 0.12
         }
     ];

     var secondTaxbands = [
         {
             min: 0,
             max: 125000,
             percent: 0.03
         },
         {
             min: 125000,
             max: 250000,
             percent: 0.05
         },
         {
             min: 250000,
             max: 925000,
             percent: 0.08
         },
         {
             min: 925000,
             max: 1500000,
             percent: 0.13
         },
         {
             min: 1500000,
             max: null,
             percent: 0.15
         }
     ];

     var tableRow = "<tr><td>{taxband}</td><td>{percent}</td><td>{taxable}</td><td class='tax'>{TAX}</td></tr>",
         table = $("#explained-table"),
         results = $("#results"),
         effectiveRate = $("#effective-rate");

         $('#calculate').on('click', function calculateButton() {
             if ($("#input-value").val() !== '') {
                calculateStampDuty();
             }
         });

         function calculateStampDuty() {

            var bands = taxbands,
                userInput = parseInt($("#input-value").val(), 10),
                row;

            if ($('#second-home').is(':checked')) {
                bands = secondTaxbands;
            }

            if (table.length) {
                table.find("tr:gt(0)").remove();
            }

            var taxableSum = function (x, y) {
                var maxBand = (x !== null) ? Math.min(x, userInput) : maxBand = userInput;
                return maxBand - y;
            },
                TAX = function (taxablesum, x) {
                return (taxablesum * x).toFixed(2);
            },
                effectiverate = function(tax) {
                    return Math.round(tax / userInput * 100).toFixed(1);
            },
                numberWithCommas = function (x) {
                var parts = x.toString().split(".");
                parts[0] = parts[0].replace(/\B(?=(\d{3})+(?!\d))/g, ",");
                return parts.join(".");
            };

                        for (var i = 0; i < bands.length; i++) { //for loop to loop through array of objects

            var min = bands[i].min, //variables to be used as arguments in functions above, not best practice to declare functions in loop
                max = bands[i].max,
                pct = bands[i].percent,
                taxablesum = taxableSum(max, min),
                tax = TAX(taxablesum, pct),
                eRate = effectiverate(tax);

            if (max !== null) { //replaces template tags with min, max and percent values in object
                row = tableRow.replace("{taxband}", "£" + min + " - " + "£" + max).replace("{percent}", (pct * 100) + "%");
            } else {
                row = tableRow.replace("{taxband}", "£" + min + "+").replace("{percent}", (pct * 100) + "%"); //used for last taxband
            }

            if (taxablesum < 0) {
                row = row.replace("{taxable}", "£" + 0 + ".00").replace("{TAX}", "£" + 0 + ".00");
            }   else if (userInput > 1500000) {
                    row = row.replace("{taxable}", "£" + numberWithCommas(taxablesum)).replace("{TAX}", "£" + numberWithCommas(tax));
                    results.text("£" + numberWithCommas(tax));
                    effectiveRate.text(eRate + "%");
            }   else if (userInput > 925000) {
                    row = row.replace("{taxable}", "£" + numberWithCommas(taxablesum)).replace("{TAX}", "£" + numberWithCommas(tax));
                    results.text("£" + numberWithCommas(tax));
                    effectiveRate.text(eRate + "%");
            }   else if (userInput > 250000) {
                    row = row.replace("{taxable}", "£" + numberWithCommas(taxablesum)).replace("{TAX}", "£" + numberWithCommas(tax));
                    results.text("£" + numberWithCommas(tax));
                    effectiveRate.text(eRate + "%");
            }   else if (userInput > 125000) {
                    row = row.replace("{taxable}", "£" + numberWithCommas(taxablesum)).replace("{TAX}", "£" + numberWithCommas(tax));
                    results.text("£" + numberWithCommas(tax));
                    effectiveRate.text(eRate + "%");
            }   else {
                    row = row.replace("{taxable}", "£" + userInput).replace("{TAX}", "£" + numberWithCommas(tax));
                    results.text("£" + (numberWithCommas(tax) * 0));
                    effectiveRate.text(eRate * 0 + "%");
            }

            table.append(row);

            console.log(Number(tax) );
        }
         }

     }());
 });

编辑
这是一个小提琴https://jsfiddle.net/p6c1w5r3/

一些按钮功能尚未完成，我想先让计算正确

最佳答案

检查这个小提琴。 https://jsfiddle.net/p6c1w5r3/7/

基本上，我们在循环外创建另一个名为totalTax的变量。然后在循环中，我们将税值添加到此变量。

最后，您不应每次都设置标签文本，而应在末尾设置一次。

哦，顺便说一句，当金额小于20000时，您的税金计算将返回奇怪的值。