array.map不是一个函数，即使我的输入正确。

Question

我想知道为什么我会收到这条错误信息？但是array.map说的对吗？

/home/ccuser/workspace/credit-card-checker/main.js:40

newArr =array.map(元素，索引) =>指数%2 === 1？元素*2: array.map )；^ validateCred :array.map不是validateCred中的函数

​

const valid1 = [4, 5, 3, 9, 6, 7, 7, 9, 0, 8, 0, 1, 6, 8, 0, 8];

const validateCred = (array) => {
  let newArr = [];
  let newestArr = [];
  let reducedResult = 0;
  const reducer = (previousValue, currentValue) => previousValue + currentValue;
  if (array.length % 2 === 0) {

    newArr = array.map((element, index) => index % 2 === 0 ? element * 2 : element);
  } else {
    newArr = array.map((element, index) => index % 2 === 1 ? element * 2 : element);
  }
  newestArr = newArr.map((element) => element > 9 ? element - 9 : element);

  let sum = newestArr.reduce((prev, curr) => prev += curr);
  return sum % 10 === 0
};

const findInvalidCards = (nestedArray) => {
  let invalidArray = [];
  invalidArray = nestedArray.forEach((element) => validateCred(element) === false);
  return invalidArray;
};

findInvalidCards(valid1);

​

Answer 1

valid1应该是一个数组，所以这里我只是包装另一组方括号。

而且，forEach总是返回未定义的，所以我将它改为使用map。

​

const valid1 = [[4, 5, 3, 9, 6, 7, 7, 9, 0, 8, 0, 1, 6, 8, 0, 8]];

const validateCred = (array) => {
  let newArr = [];
  let newestArr = [];
  let reducedResult = 0;
  const reducer = (previousValue, currentValue) => previousValue + currentValue;
  if (array.length % 2 === 0) {

    newArr = array.map((element, index) => index % 2 === 0 ? element * 2 : element);
  } else {
    newArr = array.map((element, index) => index % 2 === 1 ? element * 2 : element);
  }
  newestArr = newArr.map((element) => element > 9 ? element - 9 : element);

  let sum = newestArr.reduce((prev, curr) => prev += curr);
  return sum % 10 === 0
};

const findInvalidCards = (nestedArray) => {
  let invalidArray = [];
  invalidArray = nestedArray.map((element) => ({cardNumber: element.join(""), isValid: validateCred(element)}));
  return invalidArray;
};

console.log(findInvalidCards(valid1));

​