https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/length

Why numbers.length::: HOW THE FUCK THIS IS CALCULATED?

As i know there is no need to specify every element like this "age:age" if you are still using the same name. Only if you want to change a name of argument, like this "firstName:name"(Where "name" is argument and firstName will be name of the key in the future)

This is the problem of your solution.

JavaScript

in what language? You're supposed to return -1 for empty array, yes.

specifically for the reason you just gave: sum of nothing == 0 ;)

There is nothing between the two negative elements in the list [5,-1,-2], so why is the result 0?

I would suggest adding what you wrote: "Empty sum gives 0, no sum gives -1" or what you wrote in another reply: "[-1,-1] returns 0. [] returns -1". I understand your reasoning I'm just hoping to clear things up for beginners.

Is there issue with fixed tests and random tests? When input is empty array and my solution gives -1 for output the message from tests is: "expected -1 to equal 0". But when I change my solution and output now is 0 for empty array the message from tests is: "expected 0 to equal -1".

The tests for JS have been modified and improved over past 5 days.
And since you have not responded either, I am closing the issue.

I ran the test cases using your code, and did not have an issue with the random tests whatsoever.
They all passed.
By the way, I am using Node v12.x
I hope that helps.

JavaScript

Which language?

On "run random tests" I get this message: "expected true to equal false". But my solution gives "false" to all random tests.