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I have an array: this.entries = []. I run some code and it runs through this if statement several times:

if(this.entries[2] != null)

Everything works fine until after all the code runs I reset the array:

I've tried doing this.entries = [] and this.entries.splice(0, this.entries.length);

I re-run the code and when it gets to the if statement I get this error:

Cannot read property '2' of null

As far as I can tell there is nothing different. Tips and help would be very appreciated.

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  • Can you post your whole function please? Commented Nov 24, 2011 at 17:36

1 Answer 1

Reset to default
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There are several objects here. There is this which of course should never be null. Then there is this.entries Which is an array. Think of it as a container that can contain things. Then, there is this.entries[i] Which are the things in the container.

when this.entries[2] fails, it means that there is no object in slot 2 of the container.

However, the error Cannot read property '2' of null means that there IS NO CONTAINER. That is, the array itself has been set to null.

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2 Comments

Javascript allows you to access an array out of bounds - it gives back undefined for reads and resizes the array for writes. There is no such thing as a "null error" in this case.
Thank you for the clarification. It seems I had accidentally set the entries to null somewhere else and that was what caused it to crash.

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