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JavaScript JavaScript Loops, Arrays and Objects Tracking Multiple Items with Arrays Build a Quiz Challenge, Part 1

angelod
angelod
6,694 Points
Posted by angelod
angelod
6,694 Points

What's wrong with this?

quiz.js:26 Uncaught TypeError: Cannot read property '0' of undefined at quiz.js:26

https://w.trhou.se/1459ii3wrx

1 Answer

Steven Parker
Steven Parker
231,248 Points
Steven Parker
Steven Parker
231,248 Points

The loop on line 25 goes up to and including the length ("<="). But the largest valid index is always one less than the length, so in the final iteration the expression on line 26 tries to access an element that isn't in the array (and thus "undefined").

angelod
angelod
6,694 Points
angelod
angelod
6,694 Points

Yeah that code is a mess :/ it’s late so I’m restart it tomorrow