locomotive-boilerplate/_assets/styles/tools/_family.scss

// ==========================================================================
// Tools / Family
// ==========================================================================

// DOCS : https://lukyvj.github.io/family.scss/
//
// Select all children from the first to `$num`.
// @group with-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]
// @param {number} $num - id of the child

@mixin first($num) {
    @if $num == 1 {
        &:first-child {
            @content;
        }
    } @else {
        &:nth-child(-n + #{$num}) {
            @content;
        }
    }
}

// Select all children from the last to `$num`.
// @group with-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]
// @param {number} $num - id of the child

@mixin last($num) {
    &:nth-last-child(-n + #{$num}) {
        @content;
    }
}

// Select all children after the first to `$num`.
// @group with-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]
// @param {number} $num - id of the child

@mixin after-first($num) {
    &:nth-child(n + #{$num + 1}) {
        @content;
    }
}

// Select all children before `$num` from the last.
// @group with-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]
// @param {number} $num - id of the child

@mixin from-end($num) {
    &:nth-last-child(#{$num}) {
        @content;
    }
}

// Select all children between `$first` and `$last`.
// @group with-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]

@mixin between($first, $last) {
    &:nth-child(n + #{$first}):nth-child(-n + #{$last}) {
        @content;
    }
}

// Select all even children between `$first` and `$last`.
// @group with-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]

@mixin even-between($first, $last) {
    &:nth-child(even):nth-child(n + #{$first}):nth-child(-n + #{$last}) {
        @content;
    }
}

// Select all odd children between `$first` and `$last`.
// @group with-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]

@mixin odd-between($first, $last) {
    &:nth-child(odd):nth-child(n + #{$first}):nth-child(-n + #{$last}) {
        @content;
    }
}

// Select all `$num` children between `$first` and `$last`.
// @group with-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]

@mixin n-between($num, $first, $last) {
    &:nth-child(#{$num}n):nth-child(n + #{$first}):nth-child(-n + #{$last}) {
        @content;
    }
}

// Select all children but `$num`.
// @group with-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]
// @param {number} $num - id of the child

@mixin all-but($num) {
    &:not(:nth-child(#{$num})) {
        @content;
    }
}

// Select children each `$num`.
// @group with-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]
// @param {number} $num - id of the child
// @alias every

@mixin each($num) {
    &:nth-child(#{$num}n) {
        @content;
    }
}

// Select children each `$num`.
// @group with-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]
// @param {number} $num - id of the child

@mixin every($num) {
    &:nth-child(#{$num}n) {
        @content;
    }
}

// Select the `$num` child from the start and the `$num` child from the last.
// @group with-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]
// @param {number} $num - id of the child

@mixin from-first-last($num) {
    &:nth-child(#{$num}),
    &:nth-last-child(#{$num}) {
        @content;
    }
}

// Select the item in the middle of `$num` child. Only works with odd number
// chain.
// @group with-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]
// @param {number} $num - id of the child

@mixin middle($num) {
    &:nth-child(#{round(math.div($num, 2))}) {
        @content;
    }
}

// Select all children between the `$num` first and the `$num` last.
// @group with-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]
// @param {number} $num - id of the child

@mixin all-but-first-last($num) {
    &:nth-child(n + #{$num}):nth-last-child(n + #{$num}) {
        @content;
    }
}

// This quantity-query mixin will only select the first of `$limit` items. It will not
// work if there is not as much as item as you set in `$limit`.
// @group Quantity queries
// @param {number} $limit
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]

@mixin first-of($limit) {
    &:nth-last-child(#{$limit}):first-child {
        @content;
    }
}

// This quantity-query mixin will only select the last of `$limit` items. It will not
// if there is not as much as item as you set in `$limit`.
// @group Quantity queries
// @param {number} $limit
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]

@mixin last-of($limit) {
    &:nth-of-type(#{$limit}):nth-last-of-type(1) {
        @content;
    }
}

// This quantity-query mixin will select every items if there is at least `$num` items. It will not
// if there is not as much as item as you set in `$num`.
// @group Quantity queries
// @param {number} $limit
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]

@mixin at-least($num) {
    $selector: &;
    $child: nth(nth($selector, -1), -1);

    &:nth-last-child(n + #{$num}),
    &:nth-last-child(n + #{$num}) ~ #{$child} {
        @content;
    }
}

// This quantity-query mixin will select every items if there is at most `$num` items. It will not
// if there is not as much as item as you set in `$num`.
// @group Quantity queries
// @param {number} $limit
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]

@mixin at-most($num) {
    $selector: &;
    $child: nth(nth($selector, -1), -1);

    &:nth-last-child(-n + #{$num}):first-child,
    &:nth-last-child(-n + #{$num}):first-child ~ #{$child} {
        @content;
    }
}

// This quantity-query mixin will select every items only if there is between `$min` and `$max` items.
// @group Quantity queries
// @param {number} $limit
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]

@mixin in-between($min, $max) {
    $selector: &;
    $child: nth(nth($selector, -1), -1);

    &:nth-last-child(n + #{$min}):nth-last-child(-n + #{$max}):first-child,
    &:nth-last-child(n + #{$min}):nth-last-child(-n + #{$max}):first-child ~ #{$child} {
        @content;
    }
}

// Select the first exact child
// @group no-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]

@mixin first-child() {
    &:first-of-type {
        @content
    }
}

// Select the last exact child
// @group no-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]

@mixin last-child() {
    &:last-of-type {
        @content
    }
}

// Select all even children.
// @group no-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]

@mixin even() {
    &:nth-child(even) {
        @content;
    }
}

// Select all odd children.
// @group no-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]

@mixin odd() {
    &:nth-child(odd) {
        @content;
    }
}

// Select only the first and last child.
// @group no-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]

@mixin first-last() {
    &:first-child,
    &:last-child {
        @content;
    }
}

// Will only select the child if it’s unique.
// @group no-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]
// @alias only

@mixin unique() {
    &:only-child {
        @content;
    }
}

// Will only select the child if it’s unique.
// @group no-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]

@mixin only() {
    &:only-child {
        @content;
    }
}

// Will only select children if they are not unique. Meaning if there is at
// least 2 children, the style is applied.
// @group no-arguments
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]

@mixin not-unique() {
    &:not(:only-child) {
        @content;
    }
}

// This mixin is used to automatically sort z-index in numerical order. But it
// can also sort them in anti-numerical order, depending the parameters you use.
// @group using functions
// @content [Write the style you want to apply to the children, and it will be added within the @content directive]
// @param {number} $num - Number of children
// @param {string} $direction [forward] - Direction of the sort
// @param {number} $index [0] - Index of the sorting

@mixin child-index($num, $direction: 'forward', $index: 0) {
    @for $i from 1 through $num {
        @if ($direction == 'forward') {
            &:nth-child(#{$i}) {
                z-index: order-index($i, $index);
                @content;
            }
        } @else if ($direction == 'backward') {
            &:nth-last-child(#{$i}) {
                z-index: order-index($i, $index);
                @content;
            }
        }
    }
}

// Used by the child-index mixin. It will returned the proper sorted numbers
// depending on the `$index` value.
// @access private
// @param {number} $num - Number of children
// @param {number} $index - Index of the sorting

@function order-index($i, $index) {
    @return ($index + $i);
}