@use 'sass:list';
@use 'sass:math';
@use 'sass:meta';
@use 'sass:string';

/// Checks if a value is a relative length.
///
/// @param {*} $value - A value to be checked.
///
/// @return {Bool} True if $value is a relative length, false if it is not.
///
/// @access public
/// @group Utilities
@function is-relative-length($value) {
  $rel-length-units: (
    'em',
    'ex',
    'rex',
    'ch',
    'rem',
    '%',
    'vw',
    'vh',
    'vmin',
    'vmax',
    'svw',
    'svh',
    'svmin',
    'svmax',
    'lvw',
    'lvh',
    'lvmin',
    'lvmax',
    'dvw',
    'dvh',
    'dvmin',
    'dvmax',
    'lh',
    'rlh',
    'vb',
    'vi',
    'svb',
    'svi',
    'lvb',
    'lvi',
    'dvb',
    'dvi',
    'cap',
    'rcap',
    'ic',
    'ric',
    'cqw',
    'cqh',
    'cqi',
    'cqb',
    'cqmin',
    'cqmax',
    'fr',
    'gd'
  );

  @return (
    meta.type-of($value) == 'number' and
      list.index($rel-length-units, string.to-lower-case(math.unit($value))) !=
      null
  );
}