Question

获得未捕获的类型错误：无法设置未定义错误的属性‘0’

2019-11-24

450

javascript arrays object word-count

我正在尝试在 JavaScript 中创建一个字数统计算法，我正在创建一个 for-in 循环来从数组中获取每个单词，然后将它们推送到对象，但是在我将每个对象键设置为每个数组值时出现错误。

const wordCount = input => {
  let newArr = input.split(" ");
  let obj = {};
  for (let i in newArr) {
    console.log(newArr[i]); // This returns value
    obj.newArr[i] = 1;  // This gives error:- Uncaught TypeError: Cannot set property '0' of undefined
  }
  console.log(obj);
};
wordCount("heyy how you doin heyy");

Answer 1

const wordCount = input => {
  let newArr = input.split(" ");
  let obj = {};
  for (let i in newArr) {
   // console.log(newArr[i]); // This returns value
    obj[newArr[i]] = 1;  // This gives error:- Uncaught TypeError: Cannot set property '0' of undefined
   
  }
  console.log(obj);
};
wordCount("heyy how you doin heyy");

Answer 2

您需要将 newArr 初始化为 obj 中的一个字段：

const wordCount = input => {
  let newArr = input.split(" ");
  let obj = { newArr: [] };
  for (let i in newArr) {
    console.log(newArr[i]); // This returns value
    obj.newArr[i] = 1;  // This gives error:- Uncaught TypeError: Cannot set property '0' of undefined
  }
  console.log(obj);
};
wordCount("heyy how you doin heyy");

Answer 3

您的 obj 对象中没有属性 newArray 。

const wordCount = input => {
  let newArr = input.split(" ");
  let obj = {newArr: []};
  for (let i in newArr) {
    console.log(newArr[i]); // This returns value
    obj.newArr[i] = 1;  // This gives error:- Uncaught TypeError: Cannot set property '0' of undefined
  }
  console.log(obj);
};
wordCount("heyy how you doin heyy");