Formattting of float between -5 and 0

[jomar-honsi]

Expected behaviour

When using pointFormat with float precision 0 combined with a number between 0 and -0.5 one expects the result be be "0".

Actual behaviour

The string "-0" is displayed. This behaviour has been observed on the Dashboard climate demo, but is a Highcharts issue (see demo).

Live demo with steps to reproduce

https://jsfiddle.net/jomar_honsi/n0gm9r31/25/

• Hover over December and observe that the tooltip says "-0"

Product version

Highcharts 11.3.0

Affected browser(s)

N.A.

[hubertkozik]

Hi @jomar-honsi!

If we do something like this in Chrome browser: parseInt(-0.49999) it gives us the result -0.

This is the odd JavaScript behavior, but indeed, I think it should be handled in Highcharts.numberFormat function, which now returns the string '-0', like in this demo: https://jsfiddle.net/BlackLabel/9jnfd6s7/ (see console)

numberFormat function can be fixed with something like this: https://jsfiddle.net/BlackLabel/bdg4rej5/ Fix after comment // --- FIX, then it gives us the 0 without the minus sign.

Can I ask for your opinion @TorsteinHonsi?

[TorsteinHonsi]

The toFixed method also returns -0 in this case:

console.log(-0.4999.toFixed(0)); // => -0

According to Wikipedia, signed zeroes are used in computing. But in practice I agree it looks odd, as our formatted numbers are intended for human interpretation. I'm happy with changing the numberFormat function.

[TorsteinHonsi]

PS: The same Wikipedia article states that

Informally, one may use the notation "−0" for a negative value that was rounded to zero. This notation may be useful when a negative sign is significant; for example, when tabulating Celsius temperatures, where a negative sign means below freezing.

But we don't know that at the time of formatting, so unless we want to add another option to the number formats, I think we should just fix it.