list.select()

The list.select() function returns the list with elements selected by comparison consisting of $operand, $operator, $value, and $values....

// Sass.
@use 'sass:list';
@use 'sass:map';
@use 'sass:meta';

// Functions.
@use '../comparison/comparison.compare.function';
@use 'list.append.function' as *;
@use 'list.empty.function' as *;
@use 'list.first.function' as *;
@use 'list.index.function' as *;
@use 'list.nth.function' as *;
@use 'remove/remove.duplicate.function' as *;

// The `list.select()` function.
@function select(
  $select: index,
  $from: null,
  $operand: value,
  $operator: '==',
  $value,
  $values...
) {
  $result: ();
  $select: if(list.length($select) == 1, any $select, $select);
  $occurrence: list.nth(
    $select,
    index($select, all, any, end, first, last, only, start)
  );
  $select: list.nth($select, index($select, has, index, type, value));
  @each $value in append((), $value, comma, $values...) {
    $do: true;
    $compared-result: ();
    $index: 1;
    @while $do == true {
      $comparison-result: comparison.compare(
        map.get(
          (
            index: $index,
            type: meta.type-of(list.nth($from, $index)),
            value: list.nth($from, $index),
          ),
          $operand
        ),
        $operator,
        $value
      );

      @if $comparison-result or ($select == has and $occurrence == only) {
        $compared-result: list.append(
          $compared-result,
          map.get(
            (
              has: $comparison-result,
              index: $index,
              type: meta.type-of(list.nth($from, $index)),
              value: list.nth($from, $index),
            ),
            $select
          ),
          comma
        );
      }

      // Break the while.
      $do: if(
        $index ==
          list.length($from) or
          (
            not empty($compared-result) and list.index(first start, $occurrence)
          ),
        false,
        $do
      );
      $index: $index + 1;
    }

    $compared-result: if(empty($compared-result), null, $compared-result);

    @if $compared-result {
      @if $select == has and list.index(all only, $occurrence) {
        $compared-result: duplicate($compared-result);
        $compared-result: if(
          list.index($compared-result, null) or
            list.index($compared-result, false),
          false,
          true
        );
      }

      $compared-result: if(
        list.index(any first start end last, $occurrence),
        list.nth(
          $compared-result,
          if(
            list.index(any first start, $occurrence),
            1,
            list.length($compared-result)
          )
        ),
        if(
          list.length($compared-result) == 1,
          first($compared-result),
          $compared-result
        )
      );
    }

    $result: list.append($result, $compared-result, comma);
  }

  // has
  @if $select == has {
    $result: if(
      list.index(all, $occurrence),
      if(list.index($result, null) or list.index($result, false), false, true),
      if(
        list.index(any, $occurrence),
        if(list.index($result, true), true, false),
        if($occurrence == only, $result, false)
      )
    );
  }

  @return if(
    list.length($result) > 0,
    if(
      list.length($result) == 1 and not (type-of(nth($result, 1)) == list),
      first($result),
      $result
    ),
    null
  );
}

Parameters

`$select`

`$from`

The list to retrieve elements from, by the given comparison.

`$operand`

The value of string type can take (index, type, value) and indicates an operand from the list used in the comparison.

index

element's index

type

type of the element

value

element's value

`$operator`

not

type of

(,)

list length

(:)

map length

===

compatbile or comparable

equal to

text contains the given string (string.index())

greater than

greater or equal than

less than

less or equal than

`$value`

`$values...`

Return

The return value is the list with the elements selected by the given comparison.

Examples

// Use.
@use 'angular-package/sass/list';

// Examples.

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// Sass. @use 'sass:list'; @use 'sass:map'; @use 'sass:meta'; // Functions. @use '../comparison/comparison.compare.function'; @use 'list.append.function' as *; @use 'list.empty.function' as *; @use 'list.first.function' as *; @use 'list.index.function' as *; @use 'list.nth.function' as *; @use 'remove/remove.duplicate.function' as *; // Status: DONE // The `list.select()` function returns the list with elements selected by comparison. // @param `$select` The value of list or string type indicates what to retrieve from the given `$from` list. // The value of list type consists of occurrence and selection, in order (occurrence selection). It's changed to (selection occurrence) // when selection `has` is used, and there are (has only), (has any), (has all). // Occurrence (all, any, end, first, last, only) indicates how often compared elements occur in the given `$from` list. // Selection can take the values has, index, type, value and indicates what to retrieve from the list. // @param `$from` The list to retrieve elements from, by the given comparison. // @param `$operand` The value of string type can take (index, type, value) and indicates an operand from the list used in the comparison. // @param `$operator` The operator used to compare given `$value` and/or `$values` with `$operand` of the `$from` list. // @param `$value` The required value to select from the given `$from`. // @arbitrary `$values...` Additional values to select from the given `$from` list. // @return The return value is the list with the elements selected by the given comparison. @function select($select: index, $from: null, $operand: value, $operator: '==', $value, $values...) { $result: (); $select: if(list.length($select) == 1, any $select, $select); $occurrence: list.nth($select, index($select, all, any, end, first, last, only, start)); $select: list.nth($select, index($select, has, index, type, value)); @each $value in append((), $value, comma, $values...) { $do: true; $compared-result: (); $index: 1; @while $do == true { $comparison-result: comparison.compare( map.get((index: $index, type: meta.type-of(list.nth($from, $index)), value: list.nth($from, $index),), $operand), $operator, $value ); @if $comparison-result or ($select == has and $occurrence == only) { $compared-result: list.append( $compared-result, map.get((has: $comparison-result, index: $index, type: meta.type-of(list.nth($from, $index)), value: list.nth($from, $index)), $select), comma ); } // Break the while. $do: if($index == list.length($from) or (not empty($compared-result) and list.index(first start, $occurrence)), false, $do); $index: $index + 1; } $compared-result: if(empty($compared-result), null, $compared-result); @if $compared-result { @if $select == has and list.index(all only, $occurrence) { $compared-result: duplicate($compared-result); $compared-result: if(list.index($compared-result, null) or list.index($compared-result, false), false, true); } $compared-result: if( list.index(any first start end last, $occurrence), list.nth($compared-result, if(list.index(any first start, $occurrence), 1, list.length($compared-result))), if(list.length($compared-result) == 1, first($compared-result), $compared-result) ); } $result: list.append($result, $compared-result, comma); } // has @if $select == has { $result: if( list.index(all, $occurrence), if(list.index($result, null) or list.index($result, false), false, true), if(list.index(any, $occurrence), if(list.index($result, true), true, false), if($occurrence == only, $result, false)) ); } @return if( list.length($result) > 0, if(list.length($result) == 1 and not (type-of(nth($result, 1)) == list), first($result), $result), null ); } // Examples. $-example-list: 300px 'a' 10px 'b' 2px 'c' 15px 'd' 1px 'e' 300px 'f' 500px 'g' 3px 'h' 150px 'i' 2px; // single value // @debug select(index, 1px solid red, value, '==', 1px); // 1 // @debug select(first index, 1px solid red, value, '==', 1px); // 1 // @debug select(any index, 1px solid red, value, '==', solid); // 2 // map // @debug select(first value, (border: 1px solid red) (background: #fff), value, ':==', map); // (border: 1px solid red) // @debug select(value, (border: 1px solid red) (background: #fff), value, ':==', map); // (border: 1px solid red) // multiple values // @debug select(index, 1px solid red, value, '==', 1px, red); // 1, 3 // @debug select(first index, 1px solid red, value, '==', 1px, red); // 1, 3 // select type // @debug select(index, 1px solid red, value, '==', dashed); // null // @debug select(first index, 1px solid red, value, '==', dashed); // null // @debug select(first value, 1px solid red, value, ':==', color); // red // last occurrence // @debug select(index, 1px solid red, type, '==', string); // 2 // @debug select(last index, 1px solid red, type, '==', string); // 2 // all occurrences // @debug select(all index, 1px solid red, type, '==', string); // 2 // @debug select(all index, 1px solid red, type, '==', string, number); // 2, 1 // DONE: all/first/last index index // DONE: all/first/last index type // DONE: all/first/last index value // @debug select(all index, $-example-list, index, '==', 2, 5, 10); // 2, 5, 10 // @debug select(all index, $-example-list, type, '==', number, string, bool); // (1, 3, 5, 7, 9, 11, 13, 15, 17, 19), (2, 4, 6, 8, 10, 12, 14, 16, 18), null // @debug select(all index, $-example-list, value, '==', 1px, 2px, 3px); // 9, (5, 19), 15 // @debug select(index, $-example-list, index, '==', 2, 5, 10); // 2, 5, 10 // @debug select(first index, $-example-list, type, '==', number, string); // 1, 2 // @debug select(first index, $-example-list, value, '==', 1px, 2px, 3px); // 9, 5, 15 // @debug select(index, $-example-list, index, '==', 2, 5, 10); // 2, 5, 10 // @debug select(last index, $-example-list, tyfrom // @debug select(all value, $-example-list, index, '==', 2, 5, 10); // "a", "2px", "e" // @debug select(all value, $-example-list, type, '==', number, string); // (300px, 10px, 2px, 15px, 1px, 300px, 500px, 3px, 150px, 2px), ("a", "b", "c", "d", "e", "f", "g", "h", "i") // @debug select(all value, $-example-list, value, '==', 1px, 2px, 3px); // 1px, (2px, 2px), 3px // @debug select(first value, $-example-list, index, '==', 2, 5, 10); // "a", "2px", "e" // @debug select(first value, $-example-list, type, '==', number, string); // 300px, "a" // @debug select(first value, $-example-list, value, '==', 1px, 2px, 3px); // 1px, (2px, 2px), 3px // @debug select(value, $-example-list, index, '==', 2, 5, 10); // "a", "2px", "e" // @debug select(last value, $-example-list, type, '==', number, string); // 2px, "i" // @debug select(value, $-example-list, value, '==', 1px, 2px, 3px); // 1px, 2px, 3px // DONE: all/first/last type index // DONE: all/first/last type type // DONE: all/first/last type value // @debug select(type, $-example-list, index, '==', 2, 5, 10); // string, number, string // @debug select(all type, $-example-list, type, '==', number, string, calculation); // (number, number, number, number, number, number, number, number, number, number), (string, string, string, string, string, string, string, string, string), null // @debug select(all type, $-example-list, value, '==', 1px, 2px, 3px, 'e', 'the'); // number, (number, number), number, string, null // @debug select(first type, $-example-list, index, '==', 2, 5, 10, 100); // string, number, string, null // @debug select(first type, $-example-list, type, '==', number, string, bool); // number, string, null // @debug select(first type, $-example-list, value, ':==', number, string, bool); // number, string, null // @debug select(first type, $-example-list, value, '==', 1px, 2px, 157px, 3px, 'e', 'the'); // number, number, null, number, string, null // @debug select(type, $-example-list, index, '==', 2, 5, 10, 100); // string, number, string, null // @debug select(last type, $-example-list, type, '==', number, string, bool); // number, string, null // @debug select(last type, $-example-list, value, ':==', number, string, bool); // number, string, null // @debug select(type, $-example-list, value, '==', 1px, 2px, 157px, 3px, 'e', 'the'); // number, number, null, number, string, null // DONE: all/first/last index index // DONE: all/first/last index type // DONE: all/first/last index value // @debug select(has, $-example-list, type, '==', bool, number); // true // @debug select(has any, $-example-list, value, '==', 2px, 'f', 'the'); // true // @debug select(has all, $-example-list, value, '==', 2px, 'f', 'the', 3px); // false // @debug select(has only, 2px 2px 2px 2px, value, '==', 2px, 'f', 'the', 3px, 10px); // true, false, false, false, false // @debug select(has all, 1 'a' 2 'b' 3 'c' 4 'd' 5 'e' 6 'f' 7 'g' 8 'h' 9 'i' 10 'j', value, '==', 'e', 'f'); // true // @debug select(has all, 1 'a' 2 'b' 3 'c' 4 'd' 5 'e' 6 'f' 7 'g' 8 'h' 9 'i' 10 'j', value, '==', 'e', 'f', 6, 10, 112); // false // @debug select(has all, ('a', 'b', 'c'), value, '==', 'a', 'b', 'c', false); // @debug select(has any, ('a', 'b', 1, 2, 3, (a, b, c), 'c', 5123), value, ':==', list, number, string, bool); // @debug select(has any, ('a', 'b', 1, 2, 3, (a, b, c), 'c', 5123), value, ':==', list, number, string, bool); // different operator // @debug select(value, $-example-list, value, '>', 2, 5, 10); // 300px, 300px, 300px // @debug select(all value, $-example-list, value, '>', 2, 5, 10); // (300px, 10px, 15px, 300px, 500px, 3px, 150px), (300px, 10px, 15px, 300px, 500px, 150px), (300px, 15px, 300px, 500px, 150px) // @debug select(value, $-example-list, value, '<', 2, 5, 10); // 1px, 2px, 2px // @debug select(all value, $-example-list, value, '<', 2, 5, 10); // 1px, (2px, 1px, 3px, 2px), (2px, 1px, 3px, 2px) // @debug select(first index, $-example-list, value, '>', 2, 5, 10); // 1, 1, 1 // @debug select(first index, $-example-list, value, '<', 2, 5, 10); // 9, 5, 5 // @debug select(last index, $-example-list, value, '>', 2, 5, 10); // 17, 17, 17 // @debug select(last index, $-example-list, value, '<', 2, 5, 10); // 9, 19, 19 // @debug select(all index, $-example-list, value, '>', 2, 5, 10); // (1, 3, 7, 11, 13, 15, 17), (1, 3, 7, 11, 13, 17), (1, 7, 11, 13, 17 // @debug select(all index, $-example-list, value, '>=', 2, 5, 10); // 9, (5, 9, 15, 19), (5, 9, 15, 19) // @debug select(all index, $-example-list, value, '<', 2, 5, 10); // 9, (5, 9, 15, 19), (5, 9, 15, 19) // @debug select(all index, $-example-list, value, '<=', 2, 5, 10); // 9, (5, 9, 15, 19), (5, 9, 15, 19)