collectiveidea / awesome_nested_set
An awesome replacement for acts_as_nested_set and better_nested_set.
Awesome Nested Set Cheat Sheet
Awesome Nested Set Cheat Sheet
(Based on Bear Den Design’s post )
Basic Usage
- Create a root node:
science = Category.create!(:name => ‘Science’)
- Put a new thing inside this root node:
physics = Category.create!(:name => ‘Physics’) physics.move_to_child_of(science)
- Put another inside this “physics” node:
gravity = Category.create!(:name => ‘Gravity’) gravity.move_to_child_of(physics)
- Reload your root node:
science.reload
Now you should have something that resembles this: + science |__ physics |____ gravity
Accessing the data:
| Class methods: | |
Category.root |
the first root node |
Category.roots |
all root nodes |
| Instance methods | |
my_cat.root |
root for this node. |
my_cat.level |
the level of this object in the tree. root = 0 |
my_cat.parent |
the node’s immediate parent |
my_cat.children |
array of immediate children (just those in the next level). |
my_cat.ancestors |
array of all parents, parents’ parents, etc, excluding self. |
my_cat.self_and_ancestors |
array of all parents, parents’ parents, etc, including self. |
my_cat.siblings |
array of brothers and sisters (all at that level), excluding self. |
my_cat.self_and_siblings |
array of brothers and sisters (all at that level), including self. |
my_cat.descendants |
array of all children, childrens’ children, etc., excluding self. |
my_cat.self_and_descendants |
array of all children, childrens’ children, etc., including self. |
my_cat.leaves |
array of all descendants that have no children. |
| Instance methods: Tests | (these don’t need to hit the DB to respond) |
my_cat.root? |
true if this is a root node |
my_cat.child? |
true if this is a child node. It has a parent. |
my_cat.is_ancestor_of?(obj) |
true if nested by any obj |
my_cat.is_or_is_ancestor_of?(obj) |
true if nested by any obj or self is obj |
my_cat.is_descendant_of?(obj) |
true if self is nested under obj |
my_cat.is_or_is_descendant_of?(obj) |
true if self is nested under obj or self is obj |
my_cat.leaf? |
true if this is a leaf node. It has no children. |
