Untitled object in Mermaid Config Schema

https://mermaid.js.org/schemas/config.schema.json#/properties/elk

Abstract	Extensible	Status	Identifiable	Custom Properties	Additional Properties	Access Restrictions	Defined In
Can be instantiated	No	Unknown status	No	Forbidden	Allowed	none	config.schema.json*

elk Type

object (Details)

elk Properties

Property	Type	Required	Nullable	Defined by
mergeEdges	boolean	Optional	cannot be null	Mermaid Config
nodePlacementStrategy	string	Optional	cannot be null	Mermaid Config
nodePlacementAlignment	string	Optional	cannot be null	Mermaid Config
preset	string	Optional	cannot be null	Mermaid Config
straightenEdges	boolean	Optional	cannot be null	Mermaid Config
lineHops	Merged	Optional	cannot be null	Mermaid Config
layeringStrategy	string	Optional	cannot be null	Mermaid Config
layeringLayerBound	number	Optional	cannot be null	Mermaid Config
cycleBreakingStrategy	string	Optional	cannot be null	Mermaid Config
forceNodeModelOrder	boolean	Optional	cannot be null	Mermaid Config
considerModelOrder	string	Optional	cannot be null	Mermaid Config
keepEntryNodeOnTop	boolean	Optional	cannot be null	Mermaid Config

mergeEdges

Elk specific option that allows edges to share path where it convenient. It can make for pretty diagrams but can also make it harder to read the diagram.

mergeEdges

• is optional

• Type: boolean

• cannot be null

• defined in: Mermaid Config

mergeEdges Type

boolean

mergeEdges Default Value

The default value is:

false

nodePlacementStrategy

Elk specific option affecting how nodes are placed.

nodePlacementStrategy

• is optional

• Type: string

• cannot be null

• defined in: Mermaid Config

nodePlacementStrategy Type

string

nodePlacementStrategy Constraints

enum: the value of this property must be equal to one of the following values:

Value	Explanation
"SIMPLE"
"NETWORK_SIMPLEX"
"LINEAR_SEGMENTS"
"BRANDES_KOEPF"

nodePlacementAlignment

Elk specific option affecting Brandes-Koepf node placement alignment. BALANCED combines the four directional alignments; NONE picks the smallest result. Defaults to BALANCED for the default preset and NONE for named non-default presets.

nodePlacementAlignment

• is optional

• Type: string

• cannot be null

• defined in: Mermaid Config

nodePlacementAlignment Type

string

nodePlacementAlignment Constraints

enum: the value of this property must be equal to one of the following values:

Value	Explanation
"NONE"
"LEFTUP"
"LEFTDOWN"
"RIGHTUP"
"RIGHTDOWN"
"BALANCED"

preset

Named combination of layering, node placement, placement alignment and cycle breaking options. Explicit options override the preset for that option; the remaining preset values still apply.

default — network simplex layering, balanced Brandes-Koepf placement at the top level and inside subgraphs, and depth-first cycle breaking. Balanced placement favors centered branches and composite-state entries, sometimes at the cost of a wider or taller drawing. It does not guarantee that every edge attaches to the center of its target.

legacy — Brandes-Koepf placement with NONE alignment and ELK's own greedy cycle breaking. Reproduces the rendering before presets existed.

modelOrder — network simplex layering and top-level placement, Brandes-Koepf placement inside subgraphs, NONE alignment, and greedy model-order cycle breaking, which favors declaration order.

depthFirst — the previous default: network simplex layering and top-level placement, Brandes-Koepf placement inside subgraphs, NONE alignment, and depth-first cycle breaking.

Setting layeringStrategy, nodePlacementStrategy, nodePlacementAlignment or cycleBreakingStrategy explicitly overrides the preset for that option, including an explicit NONE alignment.

preset

• is optional

• Type: string

• cannot be null

• defined in: Mermaid Config

preset Type

string

preset Constraints

enum: the value of this property must be equal to one of the following values:

Value	Explanation
"default"
"legacy"
"modelOrder"
"depthFirst"

preset Default Value

The default value is:

"default"

straightenEdges

Straightens an edge that leaves or enters a node with a tiny step.

ELK spreads an edge's port evenly along a node's side but routes the edge down a channel whose row rarely lines up with that port exactly, leaving a staircase of a few pixels right at the border. With rounded corners the two micro-bends land on top of each other and read as a kink. Enabling this moves the channel onto the port's row and drops the step, so the edge draws as one straight line and both ports stay exactly where the layout put them.

Only the step next to a node is touched, and only when the edge continues the same way afterwards, so a real turn is never collapsed. An edge is left alone entirely when moving its run would drag the far port, or would introduce a crossing.

straightenEdges

• is optional

• Type: boolean

• cannot be null

• defined in: Mermaid Config

straightenEdges Type

boolean

straightenEdges Default Value

The default value is:

true

lineHops

Renders edge crossings as small arcs ("hops") or visible gaps, so that it is clear which line passes over which where two edges meet.

The edge that gives way loses its corner rounding for the segment carrying the hop, which is the trade for a readable crossing. Curved edges are skipped rather than rewritten, to avoid corrupting their geometry. Set to false to draw plain crossings.

lineHops

• is optional

• Type: merged type (Details)

• cannot be null

• defined in: Mermaid Config

lineHops Type

merged type (Details)

one (and only one) of

• Untitled boolean in Mermaid Config

• Untitled string in Mermaid Config

lineHops Default Value

The default value is:

true

layeringStrategy

Elk specific option deciding which layer each node is assigned to — the column in a left-to-right diagram, the row in a top-down one. This is the coarsest of the three placement decisions, so changing it moves nodes further than anything else short of altering spacing.

NETWORK_SIMPLEX aims for the fewest long edges. LONGEST_PATH pushes every node as late as it can go. COFFMAN_GRAHAM bounds how many nodes share a layer, giving a more even, block-like shape on wide graphs. MIN_WIDTH and STRETCH_WIDTH trade edge length for a narrower or wider drawing. INTERACTIVE honours positions already on the nodes.

layeringStrategy

• is optional

• Type: string

• cannot be null

• defined in: Mermaid Config

layeringStrategy Type

string

layeringStrategy Constraints

enum: the value of this property must be equal to one of the following values:

Value	Explanation
"NETWORK_SIMPLEX"
"LONGEST_PATH"
"LONGEST_PATH_SOURCE"
"COFFMAN_GRAHAM"
"MIN_WIDTH"
"STRETCH_WIDTH"
"INTERACTIVE"

layeringLayerBound

Elk specific option capping how many nodes COFFMAN_GRAHAM will put in one layer. Ignored by every other layering strategy. Lower values give a taller, narrower drawing.

layeringLayerBound

• is optional

• Type: number

• cannot be null

• defined in: Mermaid Config

layeringLayerBound Type

number

layeringLayerBound Default Value

The default value is:

4

cycleBreakingStrategy

This strategy decides how to find cycles in the graph and deciding which edges need adjustment to break loops.

cycleBreakingStrategy

• is optional

• Type: string

• cannot be null

• defined in: Mermaid Config

cycleBreakingStrategy Type

string

cycleBreakingStrategy Constraints

enum: the value of this property must be equal to one of the following values:

Value	Explanation
"GREEDY"
"DEPTH_FIRST"
"INTERACTIVE"
"MODEL_ORDER"
"GREEDY_MODEL_ORDER"

forceNodeModelOrder

The node order given by the model does not change to produce a better layout. E.g. if node A is before node B in the model this is not changed during crossing minimization. This assumes that the node model order is already respected before crossing minimization. This can be achieved by setting considerModelOrder.strategy to NODES_AND_EDGES.

forceNodeModelOrder

• is optional

• Type: boolean

• cannot be null

• defined in: Mermaid Config

forceNodeModelOrder Type

boolean

forceNodeModelOrder Default Value

The default value is:

false

considerModelOrder

Preserves the order of nodes and edges in the model file if this does not lead to additional edge crossings. Depending on the strategy this is not always possible since the node and edge order might be conflicting.

considerModelOrder

• is optional

• Type: string

• cannot be null

• defined in: Mermaid Config

considerModelOrder Type

string

considerModelOrder Constraints

enum: the value of this property must be equal to one of the following values:

Value	Explanation
"NONE"
"NODES_AND_EDGES"
"PREFER_EDGES"
"PREFER_NODES"

considerModelOrder Default Value

The default value is:

"NODES_AND_EDGES"

keepEntryNodeOnTop

Elk specific option that keeps the entry node of a recursive flow at the top of the layout.

When a flow loops back on itself (a back-edge to an earlier node), ELK's degree-based cycle-breaking has no notion of an "entry point" and may rank the first-declared node in the middle, scrambling the reading order. When enabled, the entry node of each cyclic component is pinned to the first layer so the diagram still reads from its entry. Acyclic flows always have a natural source, so this has no effect on them.

Only applies when the cyclic flow has no node without incoming edges: if the loop is fed from outside (e.g. a start node pointing into it), that component already has a natural source and nothing is pinned. Detection is also scoped per container, so cycles that cross a subgraph boundary are not detected.

keepEntryNodeOnTop

• is optional

• Type: boolean

• cannot be null

• defined in: Mermaid Config

keepEntryNodeOnTop Type

boolean

keepEntryNodeOnTop Default Value

The default value is:

false