getFullYear() is not a function - angular7

Question

I am developing web app by using Angular. When I upgrade my app to Angular7, Date function is not working. It gave me error such as
DateTime.getFullYear is not a function
It was ok before I upgraded to Angular7. In package.json:
"typescript": "^3.1.1", "#angular/cli": "~7.0.2",
"#angular/complier-cli": "~7.0.0".
What is going on?

Answer 1

Remember next time you post a question to paste the code relating to your error so that someone can have a look at it, since the same error can result from different code.
After upgrading my ng6 app to ng7 my DateTime.getFullYear worked fine, until I changed something about it, and it suddenly gave the same error. Everything seemed fine.
Checking my date object like below returned an object just the way it should
dateFunction(longdate) {
console.log(typeof(longDate)) // This returned 'object' which is correct
longDate.getFullYear() // Would get the same error here
}
So I tried passing in a fresh date object into the function, and not one being send via parameter like this:
dateFunction() {
longDate = new Date();
console.log(typeof(longDate)); // This returned 'object' which is correct
longDate.getFullYear(); // This worked fine now
}
And this would work fine, so I realized it is not my getFullYear() function that is wrong, but my parameter that is corrupt.
But here is the strange part, so I went to the parent component and did the same thing there - I deleted the old code and made a fresh longDate = new Date() and send it through to my function, and suddenly it was working. The exact same code, but I just re-wrote it.
Try creating a fresh date just before your function, pass it in and see if it works. If it works then it is not your function but the old date variable that is corrupt.
PS: I just feel that I have to say that you must use the new keyword (see examples above) when creating your initial date variable, or it will also throw the error...