When i work in react.I have shows "TypeError: Cannot read properties of undefined (reading 'pathname')" , when i want to side page to page!

CodePudding user response：

can explain more about your problem and show me source code or exmaples

CodePudding user response：

It is likely due to the fact that you're trying to access a property (of an object) which is not defined. A possible scenario is when you have an object with a nested structure like this:

{
  data: {
    id: 1,
    firstName: "John",
    lastName: "Doe",
    currentJob: {
      location: "US",
      roles: [...],
      previousJob: {
        reference: "a1b2c3",
        quitAt: ...
      }
    }
  }
}

Now, imagine you're receiving from an API call an object structured like the one above (typical example of an object displaying the account of a user) but for some reasons there is no "previousJob" associated with another user. If you tried to access its "quitAt" property through data.currentJob.previousJob.quitAt you'd get a reference error, because you won't find "previousJob" in the first place.

Two steps to take at this point:

1. investigate on the reasons why that property is missing;
2. possibly use the optional chaining operator to short-circuit the reference error with a return value of undefined (e.g. data.currentJob.previousJob?.quitAt).