Allow rounding option

[MartijnCuppens]

This option allows users to limit the default precision to what's defined in precision, but doesn't round the number if the rounded number isn't equal to the number itself. This may sound a bit vague, so let's demonstrate this with an example:

Let's assume you have configured precision: 5 and allowRounding: false:

• calc(100% / 3) will output calc(100% / 3) because calc(100% / 3) != 33.33333%
• calc(100% / 4) will output 25% because calc(100% / 4) == 25%

What's the advantage? We never have rounded numbers which can cause issues like twbs/bootstrap#27374 and we don't have expressions like calc(100% / 4) that can be simplified.

PR: #61

[alexander-akait]

/cc @MartijnCuppens problem still exists, can you provide codepen where 33.33333% !== calc(100% / 3), because browsers already do same

[MartijnCuppens]

I guess this is what you are looking for: https://codepen.io/MartijnCuppens/pen/rREmxN?editors=1010 (For some resolutions the buttons do have the same width, but in many cases they don't)

[alexander-akait]

hm looks like we potentially can break code

[alexander-akait]

I think we need new option for this, also i think we should don't round calc(100% / 3) by default (it is unsafe).

[MartijnCuppens]

#61 was about adding an option which can be disabled to keep calc when the rounded version is not the same as the original value. So by default it would have been the same.

[alexander-akait]

@MartijnCuppens 👍 Can you send a PR again? For next major version we set allowRounding: false by default because we potentially can break code, it is bad.

[XhmikosR]

@evilebottnawi You can reopen the PR.

[alexander-akait]

@XhmikosR still need rebase

[XhmikosR]

That is something @MartijnCuppens can do after you reopen it.

[MartijnCuppens]

It's now rebased

[alexander-akait]

@MartijnCuppens What do you think about disable round by default as i describe above in next major?

[MartijnCuppens]

@evilebottnawi, the true behaviour is the same as it is now (I described this in the PR description #61 (comment)). I could also call it disallowRounding and set it to false if that's clearer.

[alexander-akait]

@MartijnCuppens Maybe we can do better:

- precision: false - disable precision
- precision: 5 - 5 characters
- precision: 'safe' - as you want in this issue

?

[MartijnCuppens]

precision: 'safe' would still need some kind of precision. Lets say for some reason the generated value would be: 15.35153465435186437435513 (and this is the exact number, no numbers after the last 3). That's a pretty long number, probably something you don't want. This is why I split precision & allowRounding.