// ---------------------------------------------------------
// strip-unit
// Make a number unitless
//
// Required arguments:
// `$number` String
//
// Example of use:
// strip-unit(15px)
//
// @return Number
// ---------------------------------------------------------
@function strip-unit ($number) {
  @if type-of($number) != 'number' {
    @error 'The argument $number: `#{$number}` is of incorrect type: `#{type-of($number)}`. Type of `Number` is required!';
  }
  @else if unitless($number) {
    @warn 'The argument $number: `#{$number}` has no unit. Unit is required!';
  }

  @return $number / ($number * 0 + 1);
}