LinkModel

Import it from @grafloria/engine.

ts
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class LinkModel extends DiagramEntity

Properties

Methods

• constructor( sourcePortId: string, targetPortId: string, pathType?: 'direct' | 'orthogonal' | 'smooth' | 'bezier' )
• isSelfLoop(): boolean — Is this link a SELF-LOOP, i.e. do both ends live on the same node?

Reads the cached owning-node ids, which DiagramModel.installLink backfills for every link that reaches a diagram (including ones built with new LinkModel() + addLink, which carry no ids of their own). A link that has never been installed has no ids and is — correctly — not a self-loop as far as anything can tell.

A self-loop between two DIFFERENT ports of the same node counts, and so does one that starts and ends on the SAME port.

• getNodePairKey(): string | null — The unordered node pair this link connects, as a stable key. UNORDERED on purpose: A→B and B→A are the same visual bundle and must fan out together, or a bidirectional pair would draw both links on the same centre line. Returns null when the owning nodes are unknown.
• setSourcePort(portId: string, nodeId?: string): void — Set source port
• setTargetPort(portId: string, nodeId?: string): void — Set target port
• setPathType(pathType: 'direct' | 'orthogonal' | 'smooth' | 'bezier'): void — Set path type
• setRouter(router: LinkRouterName | undefined): void — Set the routing geometry explicitly. Clears the cached route the same way setPathType does — the old polyline belongs to the old router.
• setConnector(connector: LinkConnectorName | undefined): void — Set the polyline rendering explicitly. Pure re-render; the routed points are still valid, so the cache is NOT cleared.
• effectiveRouter(): LinkRouterName — The router actually in force: the explicit field, else derived from pathType exactly as the renderer always derived it (direct → straight, orthogonal → orthogonal, smooth/bezier → straight-with-curved-rendering).
• effectiveConnector(): LinkConnectorName — The connector actually in force: the explicit field, else implied by an explicitly axis-aligned ROUTER, else derived from pathType.

The router rung exists because { router: 'orthogonal' } with the default pathType used to draw a smooth SPLINE through Manhattan waypoints — the route was orthogonal, the picture was wavy (the screenshot audit caught the demo's own readout saying "orthogonal" over a curve). Asking for an axis-aligned router IS asking for axis-aligned rendering; rounded corners are that family's standard look. An explicit connector still overrides.

• setPoints(points: Point[]): void — Set points for custom path
• addPoint(point: Point, index?: number): void — Add point to path
• removePoint(index: number): Point | undefined — Remove point from path
• generatePath( sourcePoint: Point, targetPoint: Point, sourceDirection?: 'left' | 'right' | 'top' | 'bottom', targetDirection?: 'left' | 'right' | 'top' | 'bottom' ): void — Generate path based on type
• getCurvature(): number
• addLabel( label: Partial<LinkLabel> & { text: string } & ( | { position: number } | { slot: NonNullable<LinkLabel['slot']> } ) ): void — Add label

position is no longer required when the label names a slot — and every other LinkLabel field (html, template, slot, autoOffset, rotation…) is now carried through instead of being silently dropped. The old body hand-copied five fields, so a label created here could not be an HTML label, could not auto-rotate and could not opt into auto-placement.

• removeLabel(labelId: string): LinkLabel | undefined — Remove label by ID
• removeLabelAt(index: number): LinkLabel | undefined — Remove label by index
• updateLabel(index: number, updates: Partial<LinkLabel>): void — Update label by index
• setLabels(labels: LinkLabel[]): void — REPLACE the whole label collection — the write addLabel/updateLabel cannot express.

SetLinkLabelsCommand used to do this by assigning link.labels directly on BOTH execute and undo. A plain field write does not pass trackChange() — the one funnel collab captures from — so the command emitted ZERO ops in BOTH directions: authoring a link's labels was invisible to every other peer, and so was taking it back. (The UpdateLinkStyleCommand defect at least emitted one op on execute; this emitted none at all.) replaceStyle is the same seam for the same reason.

• override getLabel(): string | undefined — Overloaded label read.

• getLabel() — no argument — is the CANONICAL display-label accessor inherited from DiagramEntity (metadata.label, with the legacy data['label'] fallback). It is what the DSL generator exports and what feeds the renderer's simple edge label (svg-renderer reads link.getMetadata('label')).

• getLabel(labelId) is the pre-existing lookup into the POSITIONED multi-label API (labels: LinkLabel[] / addLabel / updateLabel), a different feature that happens to share the verb. The overload keeps both callable without forking the canonical name.

• override getLabel(labelId: string): LinkLabel | undefined — Overloaded label read.

• getLabel() — no argument — is the CANONICAL display-label accessor inherited from DiagramEntity (metadata.label, with the legacy data['label'] fallback). It is what the DSL generator exports and what feeds the renderer's simple edge label (svg-renderer reads link.getMetadata('label')).

• getLabel(labelId) is the pre-existing lookup into the POSITIONED multi-label API (labels: LinkLabel[] / addLabel / updateLabel), a different feature that happens to share the verb. The overload keeps both callable without forking the canonical name.

• override getLabel(labelId?: string): string | LinkLabel | undefined — Overloaded label read.

• getLabel() — no argument — is the CANONICAL display-label accessor inherited from DiagramEntity (metadata.label, with the legacy data['label'] fallback). It is what the DSL generator exports and what feeds the renderer's simple edge label (svg-renderer reads link.getMetadata('label')).

• getLabel(labelId) is the pre-existing lookup into the POSITIONED multi-label API (labels: LinkLabel[] / addLabel / updateLabel), a different feature that happens to share the verb. The overload keeps both callable without forking the canonical name.

• setState(state: 'default' | 'selected' | 'hovered' | 'highlighted'): void — Set state

• updateStyle(style: Partial<LinkStyle>): void — Update style

• replaceStyle(style: Partial<LinkStyle>): void — REPLACE the whole style object — the write updateStyle cannot express.

updateStyle merges, so it can never REMOVE a key; restoring a snapshot has to assign wholesale. UpdateLinkStyleCommand.undo() used to do that with a direct field write (link.style = restored), which never passes trackChange() — the single funnel collab captures from. Measured: execute emitted 1 op, undo emitted 0, so every peer kept the styled link forever while the author saw it correctly reverted. See collab/style-undo.spec.ts.

• setData(key: string, value: any): void — Set data property
• getData(key: string): any — Get data property
• reconnectSource(newPortId: string, newNodeId?: string): void — Reconnect source endpoint to new port Used for link reconnection workflow
• reconnectTarget(newPortId: string, newNodeId?: string): void — Reconnect target endpoint to new port Used for link reconnection workflow
• getSourceEndpoint(): Point — Get source endpoint position Returns the first point in the path (source end)
• getTargetEndpoint(): Point — Get target endpoint position Returns the last point in the path (target end)
• selectSourceEndpoint(): void — Select source endpoint handle
• selectTargetEndpoint(): void — Select target endpoint handle
• deselectEndpoints(): void — Deselect all endpoint handles
• hasSelectedEndpoint(): boolean — Check if any endpoint is selected
• getPointAtPosition(t: number): Point | null — Get point at position along link (0-1)
• getTotalLength(): number — Get total path length
• getLength(): number — Get path length (alias for getTotalLength for API consistency)
• getTangentAt(t: number): Point | null — Get tangent (direction vector) at position along path (0-1) Returns normalized direction vector
• getNormalAt(t: number): Point | null — Get normal (perpendicular vector) at position along path (0-1) Returns normalized perpendicular vector (90° counter-clockwise from tangent)
• getClosestPoint(point: Point): { point: Point; distance: number; t: number } | null — Get closest point on path to a given point Returns the closest point, distance, and normalized position (t)
• getAngleAt(t: number): number | null — Get angle at position along path (0-1) in degrees Useful for label rotation
• override serialize(): SerializedLink — Serialize to JSON
• static fromJSON(data: SerializedLink): LinkModel (static) — Deserialize from JSON