Sass svg background URI function

svg-url.scss

// https://codepen.io/tigt/post/optimizing-svgs-in-data-uris

//
//  Function to create an optimized svg url
//
@function svg-url($svg){
    //
    //  Add missing namespace
    //
    @if not str-index($svg,xmlns) {
        $svg: str-replace($svg, '<svg','<svg xmlns="http://www.w3.org/2000/svg"');   
    }        
    //    
    //  Chunk up string in order to avoid 
    //  "stack level too deep" error
    //     
    $encoded:'';
    $slice: 2000;
    $index: 0;
    $loops: ceil(str-length($svg)/$slice);
    @for $i from 1 through $loops {
        $chunk: str-slice($svg, $index, $index + $slice - 1); 
        //
        //   Encode 
        //
        $chunk: str-replace($chunk,'"', '\'');
        $chunk: str-replace($chunk,'%', '%25');
        $chunk: str-replace($chunk,'&', '%26');
        $chunk: str-replace($chunk,'#', '%23');       
        $chunk: str-replace($chunk,'{', '%7B');
        $chunk: str-replace($chunk,'}', '%7D');         
        $chunk: str-replace($chunk,'<', '%3C');
        $chunk: str-replace($chunk,'>', '%3E');
        
        // 
        //    The maybe list 
        //
        //    Keep size and compile time down
        //    ... only add on documented fail 
        // 
        //  $chunk: str-replace($chunk, '|', '%7C');
        //  $chunk: str-replace($chunk, '[', '%5B');
        //  $chunk: str-replace($chunk, ']', '%5D');
        //  $chunk: str-replace($chunk, '^', '%5E');
        //  $chunk: str-replace($chunk, '`', '%60');
        //  $chunk: str-replace($chunk, ';', '%3B');
        //  $chunk: str-replace($chunk, '?', '%3F');
        //  $chunk: str-replace($chunk, ':', '%3A');
        //  $chunk: str-replace($chunk, '@', '%40');
        //  $chunk: str-replace($chunk, '=', '%3D');      
        
        $encoded: #{$encoded}#{$chunk};
        $index: $index + $slice; 
    }
    @return url("data:image/svg+xml,#{$encoded}");   
}
        
//  Background svg mixin          
@mixin background-svg($svg){
    background-image: svg-url($svg);        
}        
            
//  Helper function to replace characters in a string
@function str-replace($string, $search, $replace: '') {
    $index: str-index($string, $search); 
    @return if($index, 
        str-slice($string, 1, $index - 1) + $replace + 
        str-replace(str-slice($string, $index + 
        str-length($search)), $search, $replace), 
        $string); 
}

// usage :
.cartman {
    @include aspect-ratio();
    width: 40%;
    margin: 40px 0;
    padding: 0;
    position: relative;
    @include background-svg($svg-cartman); // <= here :-)
    background-size: cover; 
    background-repeat:no-repeat;
    background-position:50% 50%;
}