* [`closest`](#usage-closest) | [`parent`](#usage-parent) | [`children`](#usage-children) | [`findAll`](#usage-findAll)
* [`descendants`](#usage-descendants) | [`parents`](#usage-parents) | [`parentsUntil`](#usage-parentsUntil)
* [`descendantsUntil`](#usage-descendantsUntil)
* [`next`](#usage-next) | [`prev`](#usage-prev) | [`nextSibling`](#usage-nextSibling) | [`prevSibling`](#usage-prevSibling)
* [`sibling`](#usage-sibling) | [`nextAll`](#usage-nextAll) | [`prevAll`](#usage-prevAll) | [`siblings`](#usage-siblings)
* [`nextUntil`](#usage-nextUntil) | [`prevUntil`](#usage-prevUntil)
* [`eq`](#usage-eq) | [`first`](#usage-first) | [`last`](#usage-last) | [`filterBy`](#usage-filterBy) | [`not`](#usage-not)
---
## .closest
**Description**
Travels up the DOM tree from the current element to find the first ancestor that matches the selector.
**Parameters**
* `selector` (String): A string containing a selector expression to match elements against.
**Returns**
* (jBase): A new jBase object containing the matching ancestor.
**Example**
```javascript
// Find the nearest container div for a button
const container = $('button.save').closest('.container');
```
---
## .parent
**Description**
Get the direct parent of each element in the current set of matched elements.
**Parameters**
* None.
**Returns**
* (jBase): The parent elements.
**Example**
```javascript
$('.item').parent().addClass('has-items');
```
---
## .children
**Description**
Get the children of each element in the set of matched elements, optionally filtered by a selector.
**Parameters**
* `selector` (String, optional): A string containing a selector expression to match elements against.
**Returns**
* (jBase): The children elements.
**Example**
```javascript
// Get only list items with class 'active'
$('ul.menu').children('li.active');
```
---
## .findAll
**Description**
Finds all descendant elements that match the selector.
**Parameters**
* `selector` (String): The selector to match.
**Returns**
* (jBase): The found elements.
**Example**
```javascript
// Find all spans inside the header
$('.header').findAll('span');
```
---
## .descendants
**Description**
Get all descendant elements (children, grandchildren, etc.), optionally filtered by a selector.
**Parameters**
* `selector` (String, optional): Filter for the descendants.
**Returns**
* (jBase): All descendant elements.
**Example**
```javascript
$('#tree').descendants('.leaf');
```
---
## .parents
**Description**
Get the ancestors of each element in the current set of matched elements.
**Parameters**
* `selector` (String, optional): If supplied, the ancestors are filtered.
**Returns**
* (jBase): The ancestor elements.
**Example**
```javascript
$('span').parents('div');
```
---
## .parentsUntil
**Description**
Get the ancestors of each element in the current set of matched elements, up to but not including the element matched by the selector.
**Parameters**
* `selector` (String): The selector that indicates where to stop matching ancestor elements.
* `filter` (String, optional): A string containing a selector expression to filter the returned ancestors.
**Returns**
* (jBase): The ancestor elements between the current element and the stop selector.
**Example**
```javascript
// Get all parents of .item until .container is reached
$('.item').parentsUntil('.container');
```
---
## .descendantsUntil
**Description**
Get all descendant elements, but stop searching deeper in a specific branch once the provided selector is matched.
**Parameters**
* `selector` (String): The selector that indicates where to stop the deep traversal.
**Returns**
* (jBase): The descendant elements found before hitting the stop selector.
**Example**
```javascript
// Find descendants but don't look inside nested .protected-areas
$('.root').descendantsUntil('.protected-area');
```
---
## .next
**Description**
Get the immediately following sibling of each element in the set of matched elements.
**Parameters**
* `selector` (String, optional): If supplied, the method only returns the element if it matches.
**Returns**
* (jBase): The next sibling.
**Example**
```javascript
$('.current-step').next().addClass('next-step');
```
---
## .prev
**Description**
Get the immediately preceding sibling of each element in the set of matched elements.
**Parameters**
* `selector` (String, optional): If supplied, the method only returns the element if it matches.
**Returns**
* (jBase): The previous sibling.
**Example**
```javascript
$('.step-2').prev();
```
---
## .nextSibling
**Description**
Get the immediately following DOM sibling element. Unlike `next()`, this focuses strictly on the DOM structure `nextElementSibling`.
**Parameters**
* None.
**Returns**
* (jBase): The next sibling element.
**Example**
```javascript
const nextEl = $('.current').nextSibling();
```
---
## .prevSibling
**Description**
Get the immediately preceding DOM sibling element. Unlike `prev()`, this focuses strictly on the DOM structure `previousElementSibling`.
**Parameters**
* None.
**Returns**
* (jBase): The previous sibling element.
**Example**
```javascript
const prevEl = $('.current').prevSibling();
```
---
## .sibling
**Description**
Get a single, specific sibling element. Unlike `siblings()` which returns all siblings, this method returns a specific one (e.g. the immediate next or matching a specific condition depending on implementation).
*(Note: Based on typical usage, this often acts like a directed `next` or `prev` or finds a specific single neighbor).*
**Parameters**
* `selector` (String, optional): A selector to identify the specific sibling.
**Returns**
* (jBase): The specific sibling element.
**Example**
```javascript
// Get a specific sibling with class 'active'
$('.item').sibling('.active');
```
---
## .nextAll
**Description**
Get all following siblings of each element in the set of matched elements, optionally filtered by a selector.
**Parameters**
* `selector` (String, optional): A string containing a selector expression to match elements against.
**Returns**
* (jBase): All following sibling elements.
**Example**
```javascript
// Select all elements coming after the active one
$('.active').nextAll();
```
---
## .prevAll
**Description**
Get all preceding siblings of each element in the set of matched elements, optionally filtered by a selector.
**Parameters**
* `selector` (String, optional): A string containing a selector expression to match elements against.
**Returns**
* (jBase): All preceding sibling elements.
**Example**
```javascript
// Select all elements coming before the active one
$('.active').prevAll();
```
---
## .siblings
**Description**
Get the siblings of each element in the set of matched elements.
**Parameters**
* `selector` (String, optional): If supplied, the siblings are filtered.
**Returns**
* (jBase): The sibling elements.
**Example**
```javascript
// Find all siblings that are not active
$('.active').siblings(':not(.active)');
```
---
## .nextUntil
**Description**
Get all following siblings of each element up to but not including the element matched by the selector.
**Parameters**
* `selector` (String): The selector that indicates where to stop matching following sibling elements.
* `filter` (String, optional): A selector to filter the returned siblings.
**Returns**
* (jBase): The following siblings up to the stop selector.
**Example**
```javascript
// Select all elements between header and footer
$('#header').nextUntil('#footer');
```
---
## .prevUntil
**Description**
Get all preceding siblings of each element up to but not including the element matched by the selector.
**Parameters**
* `selector` (String): The selector that indicates where to stop matching preceding sibling elements.
* `filter` (String, optional): A selector to filter the returned siblings.
**Returns**
* (jBase): The preceding siblings up to the stop selector.
**Example**
```javascript
// Select all items backwards until the start marker
$('.end-marker').prevUntil('.start-marker');
```
---
## .eq
**Description**
Reduce the set of matched elements to the one at the specified index.
**Parameters**
* `index` (Number): An integer indicating the 0-based position of the element.
**Returns**
* (jBase): The element at the index.
**Example**
```javascript
// Select the 3rd element (index 2)
$('li').eq(2).css('color', 'red');
```
---
## .first
**Description**
Reduce the set of matched elements to the first in the set.
**Parameters**
* None.
**Returns**
* (jBase): The first element.
**Example**
```javascript
$('p').first();
```
---
## .last
**Description**
Reduce the set of matched elements to the final one in the set.
**Parameters**
* None.
**Returns**
* (jBase): The last element.
**Example**
```javascript
$('p').last();
```
---
## .filterBy
**Description**
Reduce the set of matched elements to those that match the selector.
**Parameters**
* `selector` (String): The selector to match.
**Returns**
* (jBase): The filtered subset.
**Example**
```javascript
$('div').filterBy('.highlight');
```
---
## .not
**Description**
Remove elements from the set of matched elements.
**Parameters**
* `selector` (String): A string containing a selector expression to match elements against.
**Returns**
* (jBase): The subset without the matched elements.
**Example**
```javascript
$('input').not('[type="submit"]');
```