Skip to content
Branch: master
Find file History
Latest commit c317e70 Aug 16, 2019

Swim Core Framework

package documentation chat

The Swim core framework provides a lightweight, portable, dependency-free, strongly typed baseline on which to build higher level libraries. Swim Core forms the foundation on which the @swim/mesh multiplexed streaming WARP framework, and the @swim/ui and @swim/ux real-time user interface toolkits, are built. Swim Core is part of the broader Swim System framework.


The Swim core framework consists of the following component libraries:

  • @swim/core – umbrella package that depends on, and re-exports, all Swim Core libraries.
  • @swim/util – ordering, equality, and hashing; type conversions; iterators; builders; maps; caches; and assertions.
  • @swim/codec – incremental I/O; functional parsers and writers; display, debug, and diagnostic formatters; and Unicode and binary codecs.
  • @swim/args – composable command line argument parser.
  • @swim/unit – specializable unit testing framework.
  • @swim/collections – immutable, structure sharing collections, including B-trees and S-trees (sequence trees).
  • @swim/structure – generic structured data model, with support for selectors, expressions, and lambda functions. Used as a common abstract syntax tree for Recon, JSON, XML, and other data languages.
  • @swim/streamlet – stateful, streaming component model for application componets that continuously consume input state from streaming inlets, and continuously produce output state on streaming outlets.
  • @swim/dataflow – compiler from @swim/structure expressions to live-updated data models.
  • @swim/recon – bject notation with attributes, like if JSON and XML had a baby.
  • @swim/math – mathematical and geometric structures and operators.
  • @swim/time – date-time, time zone, and time interval data types, with strptime/strftime-style parsers and formatters.
  • @swim/uri – rich object model for working with Uniform Resource Identifiers and URI subcomponents, including an efficient and safe codec for parsing and writing compliant URI strings.

Swim Core has no external dependencies.



For an npm-managed project, npm install @swim/core to make it a dependency. TypeScript sources will be installed into node_modules/@swim/core/main. Transpiled JavaScript and TypeScript definition files install into node_modules/@swim/core/lib/main. And a pre-built UMD script, which bundles all @swim/core component libraries, can be found in node_modules/@swim/core/dist/main/swim-core.js.


Browser applications can load swim-core.js directly from the Swim CDN.

<script src=""></script>

Alternatively, the standalone swim-system.js script may be loaded from the Swim CDN, which bundles @swim/core along with all other @swim/system frameworks.

<script src=""></script>



@swim/core can be imported as an ES6 module from TypeScript and other ES6-compatible environments. All component libraries are re-exported, in their entirety, from the top-level @swim/core namespace.

import * as swim from "@swim/core";


@swim/core can also be used as a CommonJS module in Node.js applications. All component libraries are re-exported by the umbrella @swim/core module.

var swim = require("@swim/core");


When loaded by a web browser, the swim-core.js script adds all component library exports to the global swim namespace.

The swim-system.js script also adds all @swim/core component library exports to the global swim namespace, making it a drop-in replacement for swim-core.js when additional @swim/system frameworks are needed.



Install build dependencies:

swim-core-js $ npm install

Build script

Use the bin/build.js script to build the Swim Core framework. The build script supports compile, test, doc, and watch commands, described below. All build script commands take an optional --projects (-p) option to restrict the build to a comma-separated list of projects.

Each project supports multiple output targets; typical targets for a project include main, to build the main sources, and test, to build the test sources. A specific target can be built for a project by appending a colon (:) and the target name to the project name. For example, to build just the main sources of the util project, pass -p util:main to the build script.

Most build commands take a --devel (-d) option to expedite development builds by skipping the minification step.

Run bin/build.js help to see a complete list of build commands. Run bin/build.js <command> --help to see a list of options supported by a particular build command.

Compiling sources

Use the compile build script command to compile, bundle, and minify TypeScript sources into JavaScript universal module definitions, output to the dist subdirectory of each project. To compile all targets, of all projects, run:

swim-core-js $ bin/build.js compile

To compile a subset of projects and targets, include a --projects (-p) option, with a comma-separated list of $project:($target)? specifiers. For example, to build the main target of the codec project, and all targets of the recon project, run:

swim-core-js $ bin/build.js compile -p codec:main,recon

Running tests

Use the test build script command to compile and run unit tests. For example, to compile and test the uri project, run:

swim-core-js $ bin/build.js test -p uri

Continuous development builds

Use the watch build script command to automatically rebuild projects when dependent source files change. For example, to continuously recompile the main target of the recon project when any source file in the project–or in one of the project's transitive local dependencies–changes, run:

swim-core-js $ bin/build.js watch -p recon:main

Pass the --devel (-d) option to expedite recompilation by skipping the minification step. Add the --test (-t) option to automatically run unit tests after each successful compilation. For example, to continuosly compile and test the recon project, bypassing minification, and skipping generation of the main script, run:

swim-core-js $ bin/build.js watch -p recon:test -d -t
You can’t perform that action at this time.