@sabaki/immutable-gametree
v1.9.4
Published
An immutable game tree data type.
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@sabaki/immutable-gametree
An immutable game tree data type.
Installation
Use npm to install:
$ npm install @sabaki/immutable-gametree
Usage
const GameTree = require('@sabaki/immutable-gametree')
let tree = new GameTree()
let newTree = tree.mutate(draft => {
let id1 = draft.appendNode(draft.root.id, {B: ['dd']})
let id2 = draft.appendNode(id1, {W: ['dq']})
draft.addToProperty(id2, 'W', 'qd')
})
console.log(newTree !== tree)
// => true
console.log(tree.root.children.length)
// => 0
console.log(newTree.root.children.length)
// => 1
console.log(newTree.root.children[0].children[0].data.W)
// => ['dq', 'qd']
API
Node Object
A node is represented by an object of the following form:
{
id: <Primitive>,
data: {
[property: <String>]: <Array<Primitive>>
},
parentId: <Primitive> | null,
children: <Array<NodeObject>>
}
Currents Object
A node can have a distinguished child. You can specify the distinguished children of nodes with an object of the following form:
{
[id: <Primitive>]: <Primitive>
}
Every value is the id of the distinguished child of the node with its key as id. If the currents object doesn't specify a distinguished child for a node, the default will be the first child index-wise.
class GameTree
new GameTree([options])
options
<Object>
(optional)getId
<Function>
(optional)merger
<Function>
(optional)root
<NodeObject>
(optional)
tree.getId
<Function>
- The getId
function will be called to get an id for each
appended node. It should return a primitive value which is unique for each call.
Defaults to a simple counter.
This property will be inherited across mutations.
tree.merger
<Function>
- When appending a new node during mutations, you can instruct your
GameTree
to automatically merge your new data into an existing node when
desired. The merger function has the following signature:
(node: <NodeObject>, data: <Object>) -> <Object> | null
where node
is a merge candidate and data
the data to be appended. Return
null
if you do not want data
to be merged into the existing node
. Return
an object (representing the merged data) if you want node
to get that data
instead (and no new nodes are going to be appended).
This property will be inherited across mutations.
tree.root
<NodeObject>
- The root node.
tree.get(id)
id
<Primitive>
Searches the whole tree for a node with the specified id and returns a
node object. If a node with the specified id doesn't exist, it
will return null
. Each instance of GameTree
will maintain a cache.
Please refrain from mutating the returned object to ensure immutability.
*tree.getSequence(id)
A generator function that yields node objects, starting with
the node of the given id
and continuing with its children until we reach a
descendant which has multiple or no children.
tree.mutate(mutator)
mutator
<Function>
The mutator
will be called with a Draft
class. In the
mutator
function you will apply all your changes to the draft. Returns a new
GameTree
instance with the changes you applied to the draft, without changing
the original GameTree
instance.
We use structural sharing to make mutations fairly efficient.
tree.navigate(id, step, currents)
id
<Primitive>
step
<Integer>
currents
<CurrentsObject>
Starts at the node with the given id
, takes the specified step
forward or
backward with respect to currents
, and returns the node at the new position.
*tree.listNodes()
A generator function that yields all the nodes as node objects of the game tree.
*tree.listNodesHorizontally(startId, step)
startId
<Primitive>
step
<Integer>
-1
or-1
A generator function that yields the nodes as node objects of
the game tree by walking horizontally along the game tree (left if step
is
-1
, otherwise right) starting at the node with id startId
.
*tree.listNodesVertically(startId, step, currents)
startId
<Primitive>
step
<Integer>
-1
or-1
currents
<CurrentsObject>
A generator function that yields the nodes as node objects of
the game tree by walking vertically along given currents
(up if step
is
-1
, otherwise down) starting at the node with id startId
.
*tree.listCurrentNodes(currents)
currents
<CurrentsObject>
Equivalent to tree.listNodesVertically(tree.root.id, 1, currents)
.
*tree.listMainNodes()
Equivalent to tree.listCurrentNodes({})
.
tree.getLevel(id)
id
<Primitive>
Returns an integer denoting the level of the node with the given id
. If node
doesn't exist, it will return null
.
*tree.getSection(level)
level
<Integer>
A generator function that yields all nodes of the given level
.
tree.getCurrentHeight(currents)
currents
<CurrentsObject>
Equivalent to [...tree.listCurrentNodes(currents)].length
.
tree.getHeight()
Calculates and returns the height of the tree as an integer. This value will be cached across mutations when possible.
tree.getHash()
Calculates and returns a hash of the whole tree as a string. This value will be cached.
tree.getStructureHash()
Calculates and returns a hash of the tree structure as a string. This value will be cached across mutations when possible.
tree.onCurrentLine(id, currents)
id
<Primitive>
currents
<CurrentsObject>
Returns whether the node with the given id
is the root node or a distinguished
descendant of the root node with respect to currents
.
tree.onMainLine(id)
id
<Primitive>
Equivalent to tree.onCurrentLine(id, {})
.
tree.toJSON()
Returns tree.root
.
class Draft
draft.root
See tree.root.
draft.get(id)
id
<Primitive>
See tree.get(id).
draft.appendNode(parentId, data[, options])
parentId
<Primitive>
data
<Object>
options
<Object>
(optional)disableMerging
<Boolean>
- Default:false
Appends a new node with the given data
to the node with id parentId
. Returns
null
if operation has failed, otherwise the id of the new node. If
disableMerging
is set to true
, automatic merging via
tree.merger
will be disabled.
draft.UNSAFE_appendNodeWithId(parentId, id, data[, options])
parentId
<Primitive>
id
<Primitive>
data
<Object>
options
<Object>
(optional) - Seedraft.appendNode
Appends a new node with the given id
and data
to the node with id
parentId
. Returns false
if operation has failed, otherwise true
.
Make sure the id
provided does not already exist in the tree and that the
getId
function will never return id
. We won't do any checks for you.
draft.removeNode(id)
id
<Primitive>
Removes the node with given id
. Throws an error if specified id
represents
the root node. Returns false
if operation has failed, otherwise true
.
draft.shiftNode(id, direction)
id
<Primitive>
direction
<String>
- One of'left'
,'right'
,'main'
Changes the position of the node with the given id
in the children array of
its parent node. If direction
is 'main'
, the node will be shifted to the
first position. Returns null
if operation has failed, otherwise the new index.
draft.makeRoot(id)
id
<Primitive>
Makes the node with the given id
the root node of the mutated tree. Returns
false
if operation has failed, otherwise true
.
draft.addToProperty(id, property, value)
id
<Primitive>
property
<String>
value
<Primitive>
Adds the given value
to the specified property
of the node with the given
id
. Ignores duplicate values. If data doesn't include the given property
, it
will add it. Returns false
if operation has failed, otherwise true
.
draft.removeFromProperty(id, property, value)
id
<Primitive>
property
<String>
value
<Primitive>
Removes the given value
from the specified property
of the node with the
given id
. If property list gets empty, the property key will be removed from
data. Returns false
if operation has failed, otherwise true
.
draft.updateProperty(id, property, values)
id
<Primitive>
property
<String>
values
<Array<Primitive>>
Sets the specified property
of the node with the given id
as values
.
Refrain from mutating values
to ensure immutability. Returns false
if
operation has failed, otherwise true
.
draft.removeProperty(id, property)
id
<Primitive>
property
<String>
Removes the specified property
from the node. Returns false
if operation has
failed, otherwise true
.
Related
- crdt-gametree - An immutable, conflict-free replicated game tree data type.