Easy font face declarations using Sass lists, mixins and loops!

fonts

/**
 * The path to the fonts folder, relative to the
 * compiled stylesheet
 * 
 * @type String
 */
$font-path: "../fonts/" !default;


/**
 * A list of the project's font faces along with
 * thier associated variants
 *
 * @type List
 * Note: The format of this list is important. 
 * Do not miss the trailing comma for single line 
 * declarations
 */
$font-faces: (
 'Gotham': (
    "GothamRounded-Book" normal normal,
    "GothamRounded-Medium" bold normal
  ),
 'Valera': (
    "varelaround-regular-webfont" normal normal,
  )
) !default;


/**
 * Generates a complete font face declarations
 * where invoked
 *
 * @type mixin
 *
 * @param $font-family The with which the font family will be called
 * @param $font-path   The path to the fonts directory relative to the compiled stylesheet
 * @param $font-file   The name of the actual font file
 * @param $font-weight The font weight (normal, bold, lighter)
 * @param $font-weight The font style (normal, italic)
 *
 * Example Usage:
 * @include font-face('Open Sans', '../fonts/', 'OpenSans-regular-webfont', bold, italic)
 */
@mixin font-face($font-family, $font-path, $font-file, $font-weight: normal, $font-style: normal ) {
  @font-face {
    font-family: $font-family;
    src: url(  $font-path + $font-file + '.eot' );
    src: url( $font-path + $font-file + '.eot?#iefix') format('embedded-opentype'),
    url( $font-path + $font-file + '.woff') format('woff'),
    url( $font-path + $font-file + '.ttf') format('truetype'),
    url( $font-path + $font-file + '.svg#{$font-family}') format('svg');
    font-weight: $font-weight;
    font-style: $font-style;
  }
}

/**
 * A loop to run through each font family
 * and print the font face declarations of each
 * variant
 *
 * Dependencies
 * variable - $font-path
 * list     - $font-faces
 * mixin    - font-face
 */
@each $font in $font-faces {
  $font-family: quote( #{nth($font, 1)} );
  $font-variants: nth($font, 2);
  
  @each $variant in $font-variants {
    $font-path: $font-path !global;
    $font-file: nth($variant, 1);
    $font-weight: nth($variant, 2);
    $font-style: nth($variant, 3);
  
    @include font-face($font-family, $font-path, $font-file, $font-weight: normal, $font-style: normal )
  }
}

All rules will have the same font-weight (normal) as I tested in https://www.sassmeister.com/:

@font-face {
  font-family: "Gotham";
  src: url("../fonts/GothamRounded-Book.eot");
  src: url("../fonts/GothamRounded-Book.eot?#iefix") format("embedded-opentype"), url("../fonts/GothamRounded-Book.woff") format("woff"), url("../fonts/GothamRounded-Book.ttf") format("truetype"), url("../fonts/GothamRounded-Book.svgGotham") format("svg");
  font-weight: normal;
  font-style: normal;
}
@font-face {
  font-family: "Gotham";
  src: url("../fonts/GothamRounded-Medium.eot");
  src: url("../fonts/GothamRounded-Medium.eot?#iefix") format("embedded-opentype"), url("../fonts/GothamRounded-Medium.woff") format("woff"), url("../fonts/GothamRounded-Medium.ttf") format("truetype"), url("../fonts/GothamRounded-Medium.svgGotham") format("svg");
  font-weight: normal;
  font-style: normal;
}
@font-face {
  font-family: "Valera";
  src: url("../fonts/varelaround-regular-webfont.eot");
  src: url("../fonts/varelaround-regular-webfont.eot?#iefix") format("embedded-opentype"), url("../fonts/varelaround-regular-webfont.woff") format("woff"), url("../fonts/varelaround-regular-webfont.ttf") format("truetype"), url("../fonts/varelaround-regular-webfont.svgValera") format("svg");
  font-weight: normal;
  font-style: normal;
}

Also, all font-styles (if you edit $font-faces definition and inject differnt values for it).

I corrected it by:

@each $font-family, $font-variants in $font-faces {
	@each $variant in $font-variants {
		$font-path: $font-path !global;
		$font-file: nth($variant, 1);
		$font-weight: nth($variant, 2);
		$font-style: nth($variant, 3);

		@include font-face($font-family, $font-path, $font-file, $font-weight, $font-style )
	}
}