Error in callback for watcher "echartData": "TypeError: Cannot read properties of undefined (reading 'length')"

以下是关于"Error in callback for watcher 'echartData': 'TypeError: Cannot read properties of undefined (reading 'length')'"的解释和演示：
1. 对象属性检查

var b = {name:1}
console.log(b.hasOwnProperty('name')) // 输出：true

2. Promise执行顺序

const p1 = new Promise((resolve, reject) => {
  setTimeout(() => {
    resolve(1)
    throw new Error('p1失败信息')
  }, 2000)
})

const p2 = p1
  .then((val) => {
    console.log(val, 'p2成功返回的')
    return val + 1
  })
  .catch((err) => {
    console.log(err, 'p2失败返回的')
    return err
  })

Promise.all([p2, Promise.reject(3)])
  .then((val2) => {
    console.log(val2, 'all成功返回的')
  })
  .catch((err2) => {
    console.log(err2, 'all失败返回的')
})

相关问题

Error in callback for watcher "inventoryList": "TypeError: Cannot read properties of undefined (reading 'apply')"

这个错误提示的意思是在监视属性"inventoryList"的回调函数中发生了一个错误，具体是"TypeError: Cannot read properties of undefined (reading 'apply')"。这个错误通常是由于在定义监视器时未正确设置回调函数引起的。解决这个问题的方法是确保正确定义监视器的回调函数，并确保函数名没有拼写错误。您可以检查一下代码中与"inventoryList"相关的监视器的回调函数是否正确设置，以及是否存在拼写错误。<span class="em">1</span><span class="em">2</span><span class="em">3</span>
#### 引用[.reference_title]
- *1* [[Vue warn]: Error in callback for watcher “lss“: “TypeError: Cannot read properties of undefined](https://blog.csdn.net/apple_51931783/article/details/127049203)[target="_blank" data-report-click={"spm":"1018.2226.3001.9630","extra":{"utm_source":"vip_chatgpt_common_search_pc_result","utm_medium":"distribute.pc_search_result.none-task-cask-2~all~insert_cask~default-1-null.142^v93^chatsearchT3_1"}}] [.reference_item style="max-width: 50%"]
- *2* *3* [Error in callback for watcher “xxx“: “TypeError: Cannot read properties of undefined ...](https://blog.csdn.net/qq_45327886/article/details/126435710)[target="_blank" data-report-click={"spm":"1018.2226.3001.9630","extra":{"utm_source":"vip_chatgpt_common_search_pc_result","utm_medium":"distribute.pc_search_result.none-task-cask-2~all~insert_cask~default-1-null.142^v93^chatsearchT3_1"}}] [.reference_item style="max-width: 50%"]
[ .reference_list ]

Error in callback for watcher "sunInputsBool": "TypeError: Cannot read properties of undefined (reading 'form')"

As an AI language model, I cannot provide a specific solution without more context on the code and the error. However, this error message suggests that there is an issue with the code that is trying to access a property of an undefined variable.

One possibility is that the variable "form" is not defined or has not been initialized before it is being accessed in the code. Check if the variable is being properly declared and initialized before using it in the code.

Another possibility is that there is a typo or a syntax error in the code that is preventing the variable from being defined or accessed properly. Double-check the code for any errors in spelling or syntax that could be causing this issue.

It would be helpful to provide more information and context on the code to get a more specific answer.