Cannot read property 'target' of undefined - for loop

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I notice a mistake in my code and I would be very happy and thankful if anyone has a solution for this.

Problem is in .target.textContent === letterClass[i].textContent){

function checkLetter(e) {
  discover = null;
  //LOOP THROUGH letterClass and check, if they match the letter in the button player has chosen
  for (let i = 0; i < letterClass.length; i++) {
   if(e.target.textContent === letterClass[i].textContent){
    discover = true;
    letterClass[i].classList.add("show");
   }
  }
  return discover;
};
checkLetter();

const letterClass = document.getElementsByClassName('letter');

You call checkLetter without any parameters. Therefore 'e' in your checkLetter functions is undefined.

Check the following line and try to call the function with a valid event:

checkLetter();

Uncaught TypeError: Cannot read property of undefined In JavaScript, Uncaught TypeError: Cannot read property of undefined. JavaScript TypeError is thrown when an operand or argument passed to a function is incompatible with the type expected by that operator or function. This error occurs in Chrome Browser when you read a property or call a method on an undefined object . The posts here help me a lot on my way to find a solution for the Uncaught TypeError: Cannot read property 'value' of undefined issue. There are already here many answers which are correct, but what we don't have here is the combination for 2 answers that i think resolve this issue completely.

You’re calling checkLetter() but you’re not passing an event. The function is expecting an event which you have called e, therefore e.target is undefined.

JavaScript Error Handling - X Is Not a Function TypeError, Uncaught TypeError: Cannot read property 'foo' of undefined.​ The dreaded error we all hit at some point in JavaScript development. Could be  Uncaught TypeError: Cannot read property 'innerHTML' of null All this means is that you are trying to access a property of an object that is undefined. These usually happens when we don't test an object before using it.

Due to hoisting letterClass goes to top of the script with undefined value. Please try to set up your consts before calling functions upon them, this should help.

Seems like one of your values, with a property key of 'value' is undefined. Test that i1 , i2 and __i are defined before executing the if statements: TypeError: Cannot read property 'width' of undefined when using image() in p5.js

Update: If you use JavaScript according to ECMAScript 2020 or later, see optional chaining. TypeScript has added support for optional chaining in version 3.7. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Learn more ERROR in Cannot read property 'flags' of undefined

In Inspect I'm getting the following error: Uncaught TypeError: Cannot read property '_handle' of undefined at eval (index.js?2f37:3) at Array. ‘Undefined’ is the property of the global object. If you don’t assign any value to a variable is of type ‘undefined’. A code also return the undefined value when the evaluated variable doesn’t have any assigned value. Code structure

When I unmount a component that uses the Form component I get the following error message. Uncaught TypeError: Cannot read property '  everytime when i try to change somthing in the Alertbox they show me “ Please enter a number greater than or equal to 0” or “ cannot read property ‘settings’ of undefined” icon Best answer by Castorr91 21 December 2019, 14:54

Comments
  • Could be because you are calling checkLetter() before you set up the letterClass node list that checkLetter() needs?
  • Don't you meant to declare your constant first and then call your function with it as a parameter like checkLetter(letterClass);?
  • Hello, in my editor it ´s declared before function. Thank you for your reply. Have a great day
  • Hello, in my editor it ´s declared before function. Thank you for your reply. Have a great day