Advanced type checking in sass

Advanced Type Checking

////
// A collection of function for advanced type checking
// @author Hugo Giraudel
// @ref https://gist.github.com/HugoGiraudel/2933ef053ae0bf70ad8b
////

@function is-number($value)
  @return type-of($value) == "number"

@function is-time($value)
  @return is-number($value) and index("ms" "s", unit($value)) != null

@function is-duration($value)
  @return is-time($value)

@function is-angle($value)
  @return is-number($value) and index("deg" "rad" "grad" "turn", unit($value)) != null

@function is-frequency($value)
  @return is-number($value) and index("Hz" "kHz", unit($value)) != null

@function is-integer($value)
  @return is-number($value) and round($value) == $value

@function is-relative-length($value)
  @return is-number($value) and index("em" "ex" "ch" "rem" "vw" "vh" "vmin" "vmax", unit($value)) != null

@function is-absolute-length($value)
  @return is-number($value) and index("cm" "mm" "in" "px" "pt" "pc", unit($value)) != null

@function is-percentage($value)
  @return is-number($value) and unit($value) == "%"

@function is-length($value)
  @return is-relative-length($value) or is-absolute-length($value)

@function is-resolution($value)
  @return is-number($value) and index("dpi" "dpcm" "dppx", unit($value)) != null

@function is-position($value)
  @return is-length($value) or is-percentage($value) or index("top" "right" "bottom" "left" "center", $value) != null