CODEWITHSUNDEEP
functionsasssass-maps
Adi Purdila
Adi Purdila

Reputation: 15

Cutting down repeating code in Sass functions

I'm working on an HTML boilerplate that uses a lot of Sass to create a maintainable and easy to use code base. Part of that are a few functions:

// Returns the scale value found at $key.
@function get-type-scale($key) {
    $value: map-get($type-scale, $key);

    @if $value != null {
        @return $value;
    }

    @else {
        @warn "Unfortunately, `#{$key}` is not defined in the `$type-scale` map.";
    }
}

// Returns the line-height value found at $key.
@function get-line-height($key) {
    $value: map-get($line-heights, $key);

    @if $value != null {
        @return $value;
    }

    @else {
        @warn "Unfortunately, `#{$key}` is not defined in the `$line-heights` map.";
    }
}

// etc... I have 2 more functions like this where only the $map changes.

These functions then get called in a few mixins, like this:

// Sets font-size and line-height based on the $level.
@mixin set-type($level: 0) {
    font-size: get-type-scale($level);
    line-height: get-line-height($level);
}

While this works just fine, I don't like the fact that I'm repeating a lot of code in the functions. I've tried writing a generic function that receives a map name as a parameter, but I cannot use interpolation in map-get().

Is there a way to make the function code more elegant and as DRY as possible?

I appreciate any insights. Cheers!

Upvotes: 1

Views: 201

Answers (2)

Jakob E
Jakob E

Reputation: 4936

You could create line-height and font-size as key/value pairs in a nested map and use interpolation to print out the property in an @each loop – like:

$map:(
  0 : (line-height: 1.3, font-size: 16px),
  1 : (line-height: 1.3, font-size: 17px),
  2 : (line-height: 1.3, font-size: 18px),
  3 : (line-height: 1.4, font-size: 19px),
  4 : (line-height: 1.5, font-size: 20px)   
);

@mixin set-type($level: 0){
  $found: map-get($map, $level); 
  @if not $found { @warn 'Key `#{$level}` not found in $map!'; } 
  @else { @each $prop, $value in $found { #{$prop} : $value; } }
}


.class { @include set-type(1); } // line-height: 1.3; font-size: 17px;
.class { @include set-type(5); } // WARN: Key `5` not found in $map!

Upvotes: 0

Marvin
Marvin

Reputation: 10152

I've tried writing a generic function that receives a map name as a parameter, but I cannot use interpolation in map-get().

Unfortunately, it is not possible to create variable names from the names of other variables at all (only from its values). Furthermore, a variable only knows its value(s) and not its name which is another issue we are facing when it comes to define the variable warning messages.

I come up with a little improvement that reduces the amount of duplicated code and keeps the ease of use of the high-level function calls. Criticism of having to pass a third variable to the generic function is justified, but I simply couldn't find a clean way to avoid it.

$line-heights: (
  0: 1em,
  1: 2em
);

$type-scale: (
  0: 1em,
  1: 2em
);

// Returns the scale value found at $key.
@function get-type-scale($key) {
    @return get-value-or-warn($type-scale, $key, 'type-scale');
}

// Returns the line-height value found at $key.
@function get-line-height($key) {
    @return get-value-or-warn($line-heights, $key, 'line-heights');
}

@function get-value-or-warn($map, $key, $map-name) {
    $value: map-get($map, $key);
    
    @if $value != null {
        @return $value;
    }

    @else {
        @warn "Unfortunately, `#{$key}` is not defined in the `$#{$map-name}` map.";
    }
}

// Sets font-size and line-height based on the $level.
@mixin set-type($level: 0) {
    font-size: get-type-scale($level);
    line-height: get-line-height($level);
}

Upvotes: 1

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