@function __base-is-match($map, $props, $values, $strict-compare-flags: (), $customizer: false) {
    $length: length($props);
    $result: null;

    @if ($map == null) {
        @return if($length == 0 or $length == null, false, true);
    }

    $index: 1;
    $no-customizer: if($customizer, false, true);

    @while ($index <= $length) {
        @if if(($no-customizer and length($strict-compare-flags) > 0 and nth($strict-compare-flags, $index)),
            (nth($values, $index) != __get($map, nth($props, $index))),
            (not map-has-key($map, nth($props, $index)))) {
            @return false;
        }

        $index: $index + 1;
    }

    $index: 1;

    @while ($index <= $length) {
        $key: nth($props, $index);

        @if $no-customizer and nth($strict-compare-flags, $index) {
            $result: map-has-key($map, $key);
        } @else {
            $map-value: __get($map, $key);
            $src-value: nth($values, $index);
            $result: if($customizer,
                __exec($customizer, $map-value, $src-value, $key),
                null);

            @if ($result == null) {
                $result: __call(__base-is-equal, null, $src-value, $map-value, $customizer, true);
            }
        }

        @if (not $result) {
            @return false;
        }

        $index: $index + 1;
    }

    @return true;
}


@function __is-match($map, $source, $customizer: null, $this-arg: null) {
    $props: __keys($source);
    $length: length($props);

    @if __is-falsey($map) {
        @return __is-empty($source);
    }

    $customizer: if(__is-function($customizer), __bind-callback($customizer, $this-arg, 3), false);

    @if (not $customizer and $length == 1) {
        $key: nth($props, 1);
        $value: __get($source, $key);

        @if (__is-strict-comparable($value)) {
            @return if($map != null and $value == __get($map, $key), map-has-key($map, $key), false);
        }
    }

    $values: ();
    $strict-compare-flags: ();

    @while ($length > 0) {
        $value: __get($source, nth($props, $length));
        $values: __set($values, $length, $value);
        $strict-compare-flags: __set($strict-compare-flags, $length, __is-strict-comparable($value));
        $length: $length - 1;
    }

    $values: __to-list($values);
    $strict-compare-flags: __to-list($strict-compare-flags);

    @return __base-is-match($map, $props, $values, $strict-compare-flags, $customizer);
}


/// Performs a deep comparison between `$map` and `source` to determine if
/// `$map` contains equivalent property values. If `$customizer` is provided
/// it is invoked to compare values. If `$customizer` returns `undefined`
/// comparisons are handled by the method instead. The `$customizer` is bound
/// to `$this-arg` and invoked with three arguments; (value, other, index|key).
///
///
/// @access public
/// @group Lang
/// @param {Map} $map The map to inspect.
/// @param {Map} $source The map of property values to match.
/// @param {Function} $customizer [null] The function to customize comparing values.
/// @param {*} $this-arg [null] - The `_this` binding of `$customizer`.
/// @returns {boolean} Returns `true` if `$map` is a match, else `false`.
/// @example scss
/// $map: ( 'user': 'fred', 'age': 40 );
/// 
/// _is-match($map, ( 'age': 40 ));
/// // => true
/// 
/// _is-match($map, ( 'age': 36 ));
/// // => false
/// 
/// // using a customizer callback
/// // todo

@function _is-match($args...) {
    @return call(get-function('__is-match'), $args...);
}