@swim/collections implements data structures for key-value maps and
sequential lists, including B-tree and S-tree (implicitly indexed B-tree)
implementations. @swim/collections is written in TypeScript, but can be
used from either TypeScript or JavaScript. @swim/collections is part of
the @swim/core
framework.
The BTree class implements the OrderedMap interface from @swim/util,
and compares keys using Objects.compare, also from @swim/util. BTree
is internally immutable, enabling lightweight snapshotting via BTree.clone,
and non-destructive mutation via BTree.updated, and BTree.removed.
BTree also implements the ReducedMap interface from @swim/util,
providing storage of sub-tree reductions in b-tree nodes to support log
time recomputation of whole tree reductions after incremental updates.
The STree class implements a sequential list data type that's backed by an
implicitly indexed b-tree. Like BTree, STree supports lightweight
snapshotting via STree.clone.
STree associated a unique ID with each list item, which can be used to
reconcile concurrent, conflicting updates to the same logical list.
For an npm-managed project, npm install @swim/collections to
make it a dependency. TypeScript sources will be installed into
node_modules/@swim/collections/main. Transpiled JavaScript and TypeScript
definition files install into node_modules/@swim/collections/lib/main.
And a pre-built UMD script can be found in
node_modules/@swim/collections/dist/main/swim-collections.js.
Alternatively, the standalone swim-system.js script may be loaded
from the Swim CDN, which bundles @swim/collections together with all other
@swim/system
libraries.
When loaded by a web browser, the swim-core.js script adds all
@swim/collections library exports to the global swim namespace.
The swim-system.js script also adds all @swim/collections library exports
to the global swim namespace, making it a drop-in replacement for
swim-core.js when additional @swim/system libraries are needed.
@swim/collections
@swim/collections implements data structures for key-value maps and sequential lists, including B-tree and S-tree (implicitly indexed B-tree) implementations. @swim/collections is written in TypeScript, but can be used from either TypeScript or JavaScript. @swim/collections is part of the @swim/core framework.
Overview
B-trees
The
BTreeclass implements theOrderedMapinterface from @swim/util, and compares keys usingObjects.compare, also from @swim/util.BTreeis internally immutable, enabling lightweight snapshotting viaBTree.clone, and non-destructive mutation viaBTree.updated, andBTree.removed.BTreealso implements theReducedMapinterface from @swim/util, providing storage of sub-tree reductions in b-tree nodes to support log time recomputation of whole tree reductions after incremental updates.S-trees
The
STreeclass implements a sequential list data type that's backed by an implicitly indexed b-tree. LikeBTree,STreesupports lightweight snapshotting viaSTree.clone.STreeassociated a unique ID with each list item, which can be used to reconcile concurrent, conflicting updates to the same logical list.Installation
npm
For an npm-managed project,
npm install @swim/collectionsto make it a dependency. TypeScript sources will be installed intonode_modules/@swim/collections/main. Transpiled JavaScript and TypeScript definition files install intonode_modules/@swim/collections/lib/main. And a pre-built UMD script can be found innode_modules/@swim/collections/dist/main/swim-collections.js.Browser
Browser applications can load
swim-core.js, which comes bundled with the @swim/collections library, directly from the Swim CDN.<script src="https://cdn.swim.ai/js/latest/swim-core.js"></script>Alternatively, the standalone
swim-system.jsscript may be loaded from the Swim CDN, which bundles @swim/collections together with all other @swim/system libraries.<script src="https://cdn.swim.ai/js/latest/swim-system.js"></script>Usage
ES6/TypeScript
@swim/collections can be imported as an ES6 module from TypeScript and other ES6-compatible environments.
import * as collections from "@swim/collections";CommonJS/Node.js
@swim/collections can also be used as a CommonJS module in Node.js applications.
var collections = require("@swim/collections");Browser
When loaded by a web browser, the
swim-core.jsscript adds all @swim/collections library exports to the globalswimnamespace.The
swim-system.jsscript also adds all @swim/collections library exports to the globalswimnamespace, making it a drop-in replacement forswim-core.jswhen additional @swim/system libraries are needed.