reverse-engineering-anything/src/application/javascript/JavaScriptArtifactGraphAccumulator.ts

import {
  createJavaScriptApplicationEdge,
  createJavaScriptApplicationNode,
} from "../../domain/javascript/javascriptApplicationGraph.js";
import type {
  ApplicationEdge,
  ApplicationNode,
} from "../../domain/javascript/javascriptApplicationGraphSchemas.js";

/** Deduplicate graph entities while retaining distinct evidence observations. */
export class JavaScriptArtifactGraphAccumulator {
  readonly #nodes = new Map<string, ApplicationNode>();
  readonly #edges = new Map<string, ApplicationEdge>();

  /** Create or merge one canonical node, retaining a stable live construction reference. */
  addNode<Input extends DisplayableNodeInput>(input: Input): ApplicationNode {
    const created = createJavaScriptApplicationNode(displayableNode(input));
    const existing = this.#nodes.get(created.node_id);
    if (existing === undefined) {
      this.#nodes.set(created.node_id, created);
      return created;
    }
    const bySemanticId = new Map(
      [...existing.observations, ...created.observations].map((observation) => [
        observation.observation_id,
        observation,
      ]),
    );
    const observations = [...bySemanticId.values()].sort((left, right) =>
      left.observation_id < right.observation_id
        ? -1
        : left.observation_id > right.observation_id
          ? 1
          : 0,
    );
    // Both factories already validated and identified these observations.
    // Replacing the node retained every previous observation array through
    // path/chunk/IPC indexes when multiple paths shared an entity identity.
    existing.observations.length = 0;
    for (const observation of observations)
      existing.observations.push(observation);
    return existing;
  }

  /** Create or replace one canonical edge by semantic identifier. */
  addEdge(input: unknown): ApplicationEdge {
    const edge = createJavaScriptApplicationEdge(input);
    this.#edges.set(edge.edge_id, edge);
    return edge;
  }

  /** Return all accumulated canonical nodes. */
  nodes(): readonly ApplicationNode[] {
    return [...this.#nodes.values()];
  }

  /** Return all accumulated canonical edges. */
  edges(): readonly ApplicationEdge[] {
    return [...this.#edges.values()];
  }
}

/** Node fields whose display form is normalized before validation. */
interface DisplayableNodeInput {
  readonly observations: readonly { readonly label: string | null }[];
}

/**
 * Static findings can carry legal empty strings, such as `fetch("")`,
 * `require("")`, or a source map's `sources: [""]`. Labels must be nonempty,
 * so an empty value has no label rather than synthetic text that a real value
 * could share; literal feature seeds match labels. Identities and observation
 * properties keep the exact value.
 */
const displayableNode = (
  input: DisplayableNodeInput,
): DisplayableNodeInput => ({
  ...input,
  observations: input.observations.map((observation) => ({
    ...observation,
    label: observation.label === "" ? null : observation.label,
  })),
});