tom_som_javascript_runtime — generic JavaScript SOM runtime

> Cross-references. > tom_specs_model/doc/som_multiplatform_spec_model.md > is the SOM authority: SOM §9 decides what a runtime must contain, SOM §6 > decides the split between the generic and the typed access path, SOM §11 and > SOM §12 decide the *.md and *.docspecs.yaml formats, and SOM §19 > decides the conformance corpus this port is measured against. > tom_specs_model/doc/som_toolchains.md > decides this language plane's build and verify toolchain. This README says how > to use this package's code; those documents own the model, the formats and > the rules, and nothing here restates them.

JavaScript port of the generic TomSpecs object-model runtime (paths, model, reflection, document, validator, YAML/Markdown codecs). Zero external dependencies (Node built-ins only).

Where this fits

TomSpecs specifications are documents with a typed shape: a spec model describes which sections exist, what each may contain and how it serializes. The SOM makes that model usable from nine languages, and each language is a pair — a hand-written runtime (this package) holding everything that is the same everywhere, and a generated tom_som_javascript_v0 facade holding the typed classes for one model version. Without the split, every regeneration would rewrite the document store, the codecs and the validator; with it, the generator emits only what actually changes when the model changes.

This package is a faithful transcription of the Dart reference, tom_som_dart_runtime, and of the Python and Java ports — it invents nothing, and "faithful" is a measured claim rather than an intention: every port is validated against the same goldens, byte for byte (SOM §19). Reach for it directly when you drive the generic API by section path; otherwise install the typed facade, which pulls this in.

Overview

A SOM document is sparse and path-keyed: values live in three stores (content, form fields, list sequences) under the globally-unique section-ID path they belong to, and an absent key means "no value" rather than an empty one. SpecDocument is that store. Everything else in the package is a layer over it — the meta-model (SpecModel, SpecReflection) that makes generic navigation possible without generated classes, the byte-stable YAML and Markdown codecs, the editing and validation tiers, and the Phase-4 CodeSpecs extractor.

It holds no document values of its own and contains no generated typed classes — those belong to the per-language tom_som_<lang>_v0 packages. The public API is re-exported from tom_som_runtime/index.js.

Installation

npm install tom_som_javascript_runtime

The version tracks the TomSpecs model version, and tom_som_javascript_v0 pins the same one — upgrade both together (SOM §4.2). See readme_howtointegrate.md for every dependency route and how to pin.

Features

Modules

Module	Responsibility
`spec_paths.js`	The section-path grammar (root / child / list-item segments).
`spec_model.js`	The meta-data loader — the exported class graph ( `SpecModel` , `SpecRoot` , `SpecClass` , `SpecField` , …).
`spec_reflection.js`	Value-free enumeration + path resolution ( `SpecReflection` , `SpecResolution` , `SpecNodeKind` ).
`spec_document.js`	A sparse in-memory document — values keyed by section path.
`spec_typed_values.js`	Parse/format at the store boundary — the one place the text form of an `int` / `double` / `num` / `bool` / enum-name is decided.
`spec_editor.js`	The generic meta-model-driven modification API ( `SpecEditor` , YRD7) — typed edits over any path, without a generated facade.
`spec_validator.js`	Validates a document's values against the model.
`spec_text_pattern.js`	The portable pattern subset ( `SomTextPattern` ) — a hand-written leftmost-first backtracker over UTF-16 code units, so match spans agree with every other runtime ( `RegExp` is the ECMAScript grammar, which accepts far more than the subset and would let a pattern that only works here into the corpus).
`spec_query.js`	The lexical/structural query surface ( `SpecQueryEngine` , `SpecQuery` , `SpecQueryCursor` ) plus the flat tier-1 node projection ( `SpecNodeProjection` ).
`spec_node_creation.js`	The constrained node-creation gate ( `checkAddNode` , `SpecNodeCreator` ) — a document may only grow in ways the model permits.
`spec_codespecs_extract.js`	The Phase-4 CodeSpecs specification extract generator ( `CodeSpecsExtractor` , `CodeSpecsAreaCatalog` ) — per area, every value `@CodeSpecKind` routes there, verbatim and with provenance. Walks one `@Document` root, resolved at construction from an optional root-type argument ( `codespecs_prompt.md` §5).
`spec_document_yaml.js`	Byte-stable `*.docspecs.yaml` codec (`SOM §12`).
`spec_document_markdown.js`	DocSpecs-conform Markdown import/export codec (`SOM §11`).
`docspecs_validator.js`	Schema-free DocSpecs parse, schema loader, and never-fail-fast validator (`SOM §14`).
`som_facade.js`	Editing-facade base types ( `SomNode` , `SomScalar` , `SomList` ) for the generated `tom_som_javascript_v0` .

Quick start

const { SpecDocument } = require('tom_som_javascript_runtime');

// A sparse document keyed by section path.
const doc = new SpecDocument();
doc.setContent('SBP/content', 'A unifying order platform.');
console.log(doc.content('SBP/content'));
// A unifying order platform.

Usage

The generic path

Load the exported class graph, then resolve paths against it — no generated classes involved:

const {
  SpecModel,
  SpecReflection,
  validateDocument,
} = require('tom_som_javascript_runtime');

const model = SpecModel.fromJson(JSON.parse(metaJson));
const reflection = new SpecReflection(model);

console.log(reflection.resolve('SBP/content') !== null);
// true
console.log(validateDocument(model, doc).length === 0);
// true

Typically you drive the runtime through the generated typed facade rather than by raw section paths.

Zero external dependencies

The build host carries only Node.js — no npm packages (no js-yaml). JSON parsing uses the native JSON.parse/JSON.stringify; YAML uses a hand-rolled, dependency-free parser (yaml.js, the constrained docspecs subset, ported from the Java runtime's Yaml.java).

Building and running the tests

Correctness is defined by the shared, language-agnostic conformance corpus in tom_som_conformance/corpus, generated from the Dart reference. This port is validated against the exact same goldens every other port uses (SOM §19):

node tests/conformance_runner.js   # → "OK: N checks passed"
./run_conformance.sh               # the same, via the wrapper
node --test                        # the thin node:test wrapper
./run_tests.sh                     # conformance + the per-module suites

The runner asserts byte-for-byte equality of the YAML and Markdown encodings, the document round-trips, the Markdown→memory landing, and the reflection / validation / operations behaviour (exit 0 on success). The conformance suite is a plain-Node main() (tests/conformance_runner.js), with a thin node --test wrapper (tests/conformance.test.js).

Architecture

        typed path                          generic path
  tom_som_javascript_v0     ─────▶   SomNode / SomScalar / SomList
            │                                   │
            └───────────────┬───────────────────┘
                            ▼
                      SpecDocument         sparse, path-keyed value stores
                            │
        ┌───────────────────┼────────────────────┐
        ▼                   ▼                    ▼
  SpecReflection       SpecEditor          spec_document_yaml.js
  SpecQueryEngine      validateDocument    spec_document_markdown.js
        │
        ▼
     SpecModel  ◀── meta/spec_model.meta.json

Type	Responsibility
`SpecDocument`	The sparse, path-keyed store of a document's content, form and list values.
`SpecModel`	The exported class graph — roots, classes, fields, annotations.
`SpecReflection`	Resolves and enumerates paths against the model without reading values.
`SpecEditor`	Typed edits over any path, driven by the meta-model rather than by generated classes.
`SpecNodeCreator`	The creation gate — a document may only grow in ways the model permits.
`validateDocument`	The instance tier: a filled document's values checked against the model.
`SpecDocumentYaml`	Byte-stable `*.docspecs.yaml` encode/decode.
`SpecDocumentMarkdown`	DocSpecs-conform Markdown export, parse and round-trip.
`SpecQueryEngine`	Lexical/structural search over a document, matching with `SomTextPattern`.
`CodeSpecsExtractor`	The Phase-4 extract generator — one verbatim, cited extract per CodeSpecs area.
`SomNode` / `SomScalar` / `SomList`	The editing-facade base types the generated `tom_som_javascript_v0` classes extend.

Ecosystem

  tom_specs_model ──▶ tom_specs_clitool ──generate_som──▶ tom_som_javascript_v0
   (the model)          (the generator)                     (typed facade)
                                                                  │ depends on
                                                                  ▼
                                                  tom_som_javascript_runtime  ← this package
                                                                  │ validated against
                                                                  ▼
                                                         tom_som_conformance
                                                          (shared corpus)

Further documentation

TomSpecs subject matter — the authorities this package implements:

Document	Authority for
index.md	The catalogue of every TomSpecs subject-matter document, and the `§` citation convention.
som_multiplatform_spec_model.md	What a SOM runtime must contain, the two access paths, the `.md` and `.docspecs.yaml` formats, the validator, and the conformance corpus.
som_toolchains.md	This language plane's build and verify toolchain, and the reference host.
tom_specs_model_meta_schema.md	The on-disk schema of `meta/spec_model.meta.json`, which `SpecModel` loads.

This package — its own guides:

Guide	Covers
readme_howtointegrate.md	Every dependency route and how to pin the version.

Siblings — packages you will reach for next:

Package	What it is
tom_som_javascript_v0	The generated typed facade over this runtime — the normal path.
tom_som_dart_runtime	The Dart reference this port transcribes.
tom_som_conformance	The shared corpus and the cross-language drivers that run every port against it.

Status

Version 1.1.0, tracking the TomSpecs model version. Requires Node.js ≥ 18 (verified with Node 22.x). Covered by 10 test files; the conformance runner reports OK: 896 checks passed and ./run_tests.sh is green.