Getting Uncaught TypeError: Cannot set property '0' of undefined error

Question

我正在尝试为 JavaScript 中的字数创建一个算法，我正在创建一个 for-in 循环以从数组中获取每个字，然后将它们推送到对象，但是在我设置时出现错误每个数组值的每个对象键。

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

您需要将 newArr 初始化为 obj 中的字段：

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 2

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");

Answer 3

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");

Getting Uncaught TypeError: Cannot set property '0' of undefined error

Getting Uncaught TypeError: Cannot set property '0' of undefined error

javascript

arrays

object

word-count