javascript - 为什么我的替换方法会抛出错误？

Question

我想将 myArray 中的数字替换为“偶数”或“奇数”，但它会抛出一个错误:TypeError: val.replace is not a function

const myArray = [
  [23, 156, 25, 10, 52, 23],

  [12, 100, 23, 56, 81, 93],

  [42.5, 71, 10, 23, 35, 11, 72, 99],

  [11, 100, 99, 102, 13, 8, 12]
];

let arr = myArray.map(item => {
  return item.map(val => {
    if (val % 2 == 0) {
      val.toString();
      val.replace(val, "even");
    } else {
      val.replace(val, "odd");
    }
  });
});

console.log(arr); //TypeError: val.replace is not a function

Answer 1

您需要返回新值。

String#replace返回带有替换值的新字符串，但此处没有字符串。

const myArray = [
  [23, 156, 25, 10, 52, 23],
  [12, 100, 23, 56, 81, 93],
  [42.5, 71, 10, 23, 35, 11, 72, 99],
  [11, 100, 99, 102, 13, 8, 12]
];

let arr = myArray.map(item => {
  return item.map(val => {
    if (val % 2 == 0) {
      return "even";
    } else {
      return "odd";
    }
  });
});

console.log(arr);