Question

我想解决问题（来自https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/javascript-algorithms-and-data-structures-projects/cash-register/）。我最终在reduce方法中使用了switch语句，但是它不能像我在代码中解释的那样工作。我只是想知道为什么这行不通，如果没有其他更好的方法来解决整个问题，那么我就是不知道。

function checkCashRegister(price, cash, cid) { 
// price refer to a purchase price, cash to the money given by a client, cid to the cash-in-drawer.

// With the method below, I want to convert the cid nested array into a single value in dollar.
  let register = cid.reduce( (sum, curr) => {
    switch (curr[0]) {
      case "PENNY" : 
        sum += curr[1] * 0.01; 
        break;
      // I would continue with case "NICKEL" etc. but the switch statement doesn't work.
      default: console.log("Unexpected currency unit");
    }
    },0)

    console.log(register);
} 

checkCashRegister(19.5, 20, [["PENNY", 1.01], ["NICKEL", 2.05], ["DIME", 3.1], ["QUARTER", 4.25], ["ONE", 90], ["FIVE", 55], ["TEN", 20], ["TWENTY", 60], ["ONE HUNDRED", 100]]);

我希望输出为0.0101，但“ console.log（register）”的实际输出为：

    Unexpected currency unit
    Unexpected currency unit
    Unexpected currency unit
    Unexpected currency unit
    Unexpected currency unit
    Unexpected currency unit
    Unexpected currency unit
    Unexpected currency unit

Answer 1

Array.reduce要求您返回一个值。您的切换语句很好。我在您的reduce函数的末尾添加了return sum;。

function checkCashRegister(price, cash, cid) { 
// price refer to a purchase price, cash to the money given by a client, cid to the cash-in-drawer.

// With the method below, I want to convert the cid nested array into a single value in dollar.
  let register = cid.reduce( (sum, curr) => {
    switch (curr[0]) {
      case "PENNY" : 
        sum += curr[1] * 0.01; 
        break;
      // I would continue with case "NICKEL" etc. but the switch statement doesn't work.
      default: console.log("Unexpected currency unit");
    }
    return sum;
  },0)

  console.log(register);
}

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduce

您确实需要做一些工作才能回答您链接的问题，但是我敢肯定您会到达那里。祝你好运。

如何在reduce方法中使用switch语句？

1 个答案: