Nested Set Keystone field type

Add nested set field for Keystone headless CNS. It allows you to create and manipulate with tree-like structures with child and parent items.

Nested Set model

The Nested Set model is described here: https://en.wikipedia.org/wiki/Nested_set_model

This module stores nested set data in the database using field names: left, rigth, depth

Graphql Scheme

Output

• left: Int
• right: Int
• depth: Int
• weight: Int // Serial number through current branch
• parentId: ID// Keystone id of direct parent element
• isLeaf: Boolean, true if have no children
• childrenCount // counts children

Filters

• parentId: type ID // Keystone id of direct parent element
• childOf // filters all elements that are children of that Keystone id
• parentOf // filters all elements that are parent of that Keystone id
• prevSiblingOf: ID! // left sibling element, null if absent
• nextSiblingOf: ID! // right sibling element, null if absent

Mutation

Create and Update

• parentId: ID // Keystone id of direct parent element
• prevSiblingId: ID // Keystone id of left sibling element
• nextSiblingId: ID // Keystone id of right sibling element

Delete

If node has children they move to the parent of deleted node.

Recompiling

The module requires to be compiled with the same major versions of the NPM modules:

• keystone-6/core
• @keystone-ui/core
• @keystone-ui/fields
• graphql

So, if you get problems on launching Keystone with this module, getting these errors:

• Schema must contain uniquely named types but contains multiple types named "OrderDirection".
• Duplicate "graphql" modules cannot be used at the same time

You need to change dependencies to the exact ones, that is uses in your application and in the keystone-6/core package.

Recompiling procedure in case you have the Keystone Core from sources in your project.

1. Create a link to the sources of both projects - execute this command on each directory:

yarn link

2. In your project directory: cleanup the node_modules folder, link the Nested Set module, and preconstruct:

rm -rf ./node-modules && yarn link && yarn link keystone-field-nested-set && yarn preconstruct && yarn install

3. In keystone-nested-set directory: build with linked Keystone sources:

rm -rf ./node-modules && yarn link @keystone-6/core && yarn && yarn build

4. On your project directory: build with recently rebuilt Nested Set module:

yarn build