CODEWITHSUNDEEP
sass
SuperDJ
SuperDJ

Reputation: 7661

How to calculate with SCSS variables from function

I have a function which converts px to rem. For example:

height: rem-calc(14px); // makes height: 1rem;

Now I would like to calculate with it from variables. For example:

$switch-track-width: rem-calc(50px);
$switch-thumb-size: $switch-track-width / 2; // making it 25px or 1.7857rem in this case

That doesn't work so I tried something else:

$switch-thumb-size: ($switch-track-width / 2) + 0rem;
$switch-thumb-size: (#{$switch-track-width} / 2) + 0rem;

Both $switch-thumb-size examples aren't working either. Now this is dividing but I'm also unable to get times (*), plus (+) and minus (-) working.

I'm also having a problem when calculating with 2 variables. For example:

$switch-track-height: rem-calc(14px);
$switch-track-width: rem-calc(50px);
$switch-thumb-right: $switch-track-height - $switch-track-width;

I prever to keep the function inside the variable instead of in the property like: height: rem-calc($switch-track-height);.

If someone could tell me how to calculate with SCSS variables on both examples that would be very helpful.

Thanks in advance

Upvotes: 24

Views: 38570

Answers (2)

delta
delta

Reputation: 101

It is actually possible to enter a formula that is compiled to a number: (first example taken from https://sass-lang.com/guide)

article[role="main"] {
  float: left;
  width: 600px / 960px * 100%;
}
div {
  width: $icon_width + 10px * 2;
}

compiles to 

article[role="main"] {
  float: left;
  width: 62.5%;
}
div {
  width: 60px;
}

This only works with compatible units. Otherwise go with someting like

height: calc( 100vh - #{$head_height} - #{$main_height});

Upvotes: 10

SuperDJ
SuperDJ

Reputation: 7661

I managed to find something that is some what working. For example:

$switch-thumb-size: rem-calc(10px);
$switch-track-height: rem-calc(20px);
$something: calc( ( #{$switch-thumb-size} - #{$switch-track-height} ) / 2 );

This results in:

calc( ( 0.71428rem - 1.4285rem ) / 2 )

But there are problems with it. First if you know that what you calculated should always be minus and you therefor add a - sign infront of the variable it will not work. Example:

height: - $something; // Doesn't work

The second problem I have with this method is that it creates a lot of redundant characters.

Because it actually puts: height: calc( ( 0.71428rem - 1.4285rem ) / 2 ) in your css instead of: height: -0.35684rem

Upvotes: 30

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