_mappy-breakpoints.scss

// Mappy breakpoints
// -----------------
// Output media query with focus on min-width, max-width, min-height and max-height.
// Other media rules are passed as the second argument in a map
//
// @author Zell Liew
// =================
$breakpoints: () !default;
$mappy-queries: () !default;

// Mappy BP [Mixin]
// ----------------
// - $queries         : <string> or <number> in the format:
//                      <min-width> <max-width> h <min-height> <max-height> <key> <value>
// - $type            : <media-type>
// - $query-fallback  : <string> selector class
// - $breakpoints     : <map>
@mixin mappy-bp($queries, $type: all, $query-fallback: null, $breakpoints: $breakpoints) {

  // Gets mappy map through mappy-bp fn
  $mappy-map: mappy-bp($queries, $type, $query-fallback, $breakpoints);

  // Outputs media string
  @media #{map-get($mappy-map, type)} and #{map-get($mappy-map, media-string)} {
    @content;
  }

  // If a query fallback is provided
  @if $query-fallback {
    #{$query-fallback} & {
      @content;
    }
  }
}

// Mappy Query [Mixin]
// -------------------
// Output query from $mappy-queries map.
// $query : <string> from $mappy-queries key
@mixin mappy-query($query, $mappy-queries: $mappy-queries) {
  @if not map-has-key($mappy-queries, $query) {
    @error "#{$mappy-queries} does not contain #{$query}";
  }

  $mappy-map: map-get($mappy-queries, $query);

  @media #{map-get($mappy-map, type)} and #{map-get($mappy-map, media-string)} {
    @content;
  }

  // If a query fallback is provided
  @if map-get($mappy-map, query-fallback) {
    #{map-get($mappy-map, query-fallback)} & {
      @content;
    }
  }
}

// Mappy BP [Function]
// -------------------
// Returns a map with 3 keys
// - type           : Media type
// - media-string   : media query string
// - query-fallback : query fallback (if any)
@function mappy-bp($queries, $type: all, $query-fallback: null, $breakpoints: $breakpoints) {
  $media-string: ();
  $_return: ();
  $media-map: parse-bp($queries, $breakpoints);

  @each $key, $value in $media-map {
    @if $value and $value != 0 {
      @if $media-string == (()) {
        $media-string: append($media-string, unquote("(#{$key}: #{$value})"));
      }

      @else {
        $media-string: append($media-string, unquote("and (#{$key}: #{$value})"));
      }
    }
  }
  $_return: (
    type: $type,
    media-string: implode($media-string),
    query-fallback: $query-fallback
  );

  @return $_return;
}

// BP [Mixin]
// ----------
// Convenience mixin for Mappy Breakpoints
@mixin bp($queries, $type: all, $query-fallback: null, $breakpoints: $breakpoints) {
  @include mappy-bp($queries, $type, $query-fallback, $breakpoints) {
    @content;
  }
}

// Parse BP [function]
// -------------------
// Parses arguments and returns a map with 4 keys
@function parse-bp($queries, $breakpoints) {
  $_return: ();
  $_i: 1;
  $_minw: null;
  $_maxw: null;
  $_minh: null;
  $_maxh: null;
  $_length: length($queries);

  // Checks for width queries
  $_minw: nth($queries, 1);
  $_minw: mappy-validate($_minw, $breakpoints);

  // Check for width queries
  @if $_minw {
    $_minw: mappy-convert-to-em($_minw);
    $_return: map-merge($_return, (min-width: $_minw));
    $queries: set-nth($queries, 1, null);
  }

  // Checks if there is a max width query
  @if $_minw and $_length >= 2 {
    $_maxw: nth($queries, 2);
    $_maxw: mappy-validate($_maxw, $breakpoints);
  }

  @if $_maxw {
    $_maxw: mappy-convert-to-em($_maxw - 1px);
    $_return: map-merge($_return, (max-width: $_maxw));
    $queries: set-nth($queries, 2, null);
  }

  // Checks for height queries
  $_h: index($queries, h) or index($queries, height);

  @if $_h {
    $_minh: nth($queries, $_h + 1);
    $_minh: mappy-validate($_minh, $breakpoints);

    @if $_minh {
      $_minh: mappy-convert-to-em($_minh);
      $_return: map-merge($_return, (min-height: $_minh));
      $queries: set-nth($queries, $_h + 1, null);
    }

    // Checks if there is a max height query
    @if $_length - $_h >= 2 {
      $_maxh: nth($queries, $_h + 2);
      $_maxh: mappy-validate($_maxh, $breakpoints);
    }

    @if $_maxh {
      $_maxh: mappy-convert-to-em($_maxh - 1px);
      $_return: map-merge($_return, (max-height: $_maxh));
      $queries: set-nth($queries, $_h + 2, null);
    }
    // Reset h marker
    $queries: set-nth($queries, $_h, null);
  }

  // Checks for other queries
  @while $_i <= length($queries) {
    $_key: nth($queries, $_i);

    @if $_key and $_length - $_i >= 1 {
      $_val: nth($queries, $_i + 1);
      $_return: map-merge($_return, (#{$_key}: $_val));
      $queries: set-nth($queries, $_i, null);
      $queries: set-nth($queries, $_i + 1, null);
    }

    @else if $_key {
      @warn unquote('"Mappy Breakpoints is missing value for media feature "#{$_key}""');
    }
    $_i: $_i + 1;
  }
  @return $_return;
}

// Mappy Validate [Function]
// -------------------------
// Checks if $query given is one of the following:
// 1) Is a $key in the $breakpoints map
// 2) Is a number
// 3) Is a "max", "max-width" or "max-height" string
@function mappy-validate($query, $breakpoints) {
  $_return: null;

  @if map-has-key($breakpoints, $query) {
    $_return: map-get($breakpoints, $query);
  }

  @else if type-of($query) == number {
    $_return: $query;
  }

  @else if $query == "max" or $query == "max-height" or $query == "max-width" {
    $_return: 0;
  }

  @else {
    $_return: null;
  }
  @return $_return;
}

// Mappy Convert To Em [Function]
// -------------------------------
// Checks and converts px values to em. Leave other units untouched.

@function mappy-convert-to-em($val) {
  @if unit($val) == "px" or $val == 0 {
    @return mappy-em($val);
  } @else if unit($val) == "em" {
    @return $val;
  } @else if unit($val) == "rem" {
    @return mappy-strip-unit($val) * 1em;
  } @else {
    @error unquote("Breakpoint value must have a unit if it's a number");
  }
}

// Mappy Em [Function]
// --------------------
// Converts pixels to em with $base-font-size
// - https://gist.github.com/ijy/1441967
@function mappy-em($target, $context: 16px) {
  @if $target == 0 {
    @return 0;
  }
  @return $target / $context * 1em;
}

@function mappy-strip-unit($num) {
  @return $num / ($num * 0 + 1);
}

// Implode [Function]
// --------------------
// Implode a list into a string
@function implode($list, $glue: ' ') {
  $res: null;
  $len: length($list);

  @for $i from 1 through $len {
    $e: nth($list, $i);
    @if $i == $len {
      $res: $res#{$e};
    }
    @else {
      $res: $res#{$e}#{$glue};
    }
  }

  @return $res;
}