node_modules/material-icons/iconfont/mixins.scss

@function material-icons-str-replace($string, $search, $replace: '') {
  $index: str-index($string, $search);

  @if $index {
    @return str-slice($string, 1, $index - 1) + $replace + material-icons-str-replace(str-slice($string, $index + str-length($search)), $search, $replace);
  }

  @return $string;
}

@function material-icons-content($codepoint) {
  @return unquote('"\\#{$codepoint}"');
}

@mixin material-icons(
  $font-size: $material-icons-font-size,
  $font-family: $material-icons-font-family
) {
  font-family: $font-family;
  font-weight: normal;
  font-style: normal;
  font-size: $font-size;
  display: inline-block;
  line-height: 1;
  text-transform: none;
  letter-spacing: normal;
  word-wrap: normal;
  white-space: nowrap;
  direction: ltr;

  /* Support for all WebKit browsers. */
  -webkit-font-smoothing: antialiased;
  /* Support for Safari and Chrome. */
  text-rendering: optimizeLegibility;

  /* Support for Firefox. */
  -moz-osx-font-smoothing: grayscale;

  /* Support for IE. */
  font-feature-settings: 'liga';
}

@mixin material-icon($name, $pseudo: 'before') {
  $codepoint: map-get($material-icons-codepoints, $name);

  &:#{$pseudo} {
    content: material-icons-content($codepoint);
  }
}