SASS function to create an inline SVG url() source.

svg-url.scss

/*
 * Replacing SVG strings in data-uri style situations
 * by Jakob Erikson -- https://github.com/jakob-e
 *
 * http://codepen.io/jakob-e/pen/doMoML
 */

//  Function to replace characters in a string
@function str-replace($string, $search, $replace: '') {
  $index: str-index($string, $search);
  @if $index {
    @return str-slice($string, 1, $index - 1) + $replace +
    str-replace(str-slice($string, $index +
    str-length($search)), $search, $replace);
  }
  @return $string;
}


//  Function to create an optimized svg url
@function svg-url($svg){
  // Chunk up string in order to avoid "SystemStackError: stack level too deep"
  $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);
    $chunk: str-replace($chunk,'"','\'');
    $chunk: str-replace($chunk,'<','%3C');
    $chunk: str-replace($chunk,'>','%3E');
    $chunk: str-replace($chunk,'&','%26');
    $chunk: str-replace($chunk,'#','%23');
    $encoded: #{$encoded}#{$chunk};
    $index: $index + $slice;
  }
  @return url("data:image/svg+xml;charset=utf8,#{$encoded}");
}