mermaidAPI

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This is the API to be used when optionally handling the integration with the web page, instead of using the default integration provided by mermaid.js.

The core of this api is the render function which, given a graph definition as text, renders the graph/diagram and returns an SVG element for the graph.

It is is then up to the user of the API to make use of the SVG, either insert it somewhere in the page or do something completely different.

In addition to the render function, a number of behavioral configuration options are available.

Configuration

Configuration methods in Mermaid version 8.6.0 have been updated, to learn more[click here].

What follows are config instructions for older versions

These are the default options which can be overridden with the initialization call like so:

Example 1:

 mermaid.initialize({ flowchart:{ htmlLabels: false } });

Example 2:

 <script> var config = { startOnLoad:true, flowchart:{ useMaxWidth:true,
htmlLabels:true, curve:'cardinal', },
securityLevel:'loose',

}; mermaid.initialize(config); </script>

A summary of all options and their defaults is found here. A description of each option follows below.

theme

Theme , the CSS style sheet

Parameter	Description	Type	Required	Values
theme	Built in Themes	string	Optional	'default', 'forest', 'dark', 'neutral', 'null'

Notes: To disable any pre-defined mermaid theme, use "null".

 "theme": "forest",
"themeCSS": ".node rect { fill: red; }"

fontFamily

Parameter	Description	Type	Required	Values
fontFamily	specifies the font to be used in the rendered diagrams	string	Required	Any Possible CSS FontFamily

Notes: Default value: '"trebuchet ms", verdana, arial, sans-serif;'.

logLevel

Parameter	Description	Type	Required	Values
logLevel	This option decides the amount of logging to be used.	string \| number	Required	1, 2, 3, 4, 5

Notes:

Debug: 1
Info: 2
Warn: 3
Error: 4
Fatal: 5 (default)

securityLevel

Parameter	Description	Type	Required	Values
securitylevel	Level of trust for parsed diagram	string	Required	'strict', 'loose', 'antiscript'

Notes:

strict: (default) tags in text are encoded, click functionality is disabled
loose: tags in text are allowed, click functionality is enabled
antiscript: html tags in text are allowed, (only script element is removed), click functionality is enabled

startOnLoad

Parameter	Description	Type	Required	Values
startOnLoad	Dictates whether mermaid starts on Page load	boolean	Required	true, false

Notes: Default value: true

arrowMarkerAbsolute

Parameter	Description	Type	Required	Values
arrowMarkerAbsolute	Controls whether or arrow markers in html code are absolute paths or anchors	boolean	Required	true, false

Notes:

This matters if you are using base tag settings.

Default value: false

secure

This option controls which currentConfig keys are considered secure and can only be changed via call to mermaidAPI.initialize. Calls to mermaidAPI.reinitialize cannot make changes to the secure keys in the current currentConfig. This prevents malicious graph directives from overriding a site's default security.

Notes:

Default value: ['secure', 'securityLevel', 'startOnLoad', 'maxTextSize']

deterministicIds

This option controls if the generated ids of nodes in the SVG are generated randomly or based on a seed. If set to false, the IDs are generated based on the current date and thus are not deterministic. This is the default behaviour.

Notes:

This matters if your files are checked into sourcecontrol e.g. git and should not change unless content is changed.

Default value: false

deterministicIDSeed

This option is the optional seed for deterministic ids. if set to undefined but deterministicIds is true, a simple number iterator is used. You can set this attribute to base the seed on a static string.

flowchart

The object containing configurations specific for flowcharts

diagramPadding

Parameter	Description	Type	Required	Values
diagramPadding	Amount of padding around the diagram as a whole	Integer	Required	Any Positive Value

Notes:

The amount of padding around the diagram as a whole so that embedded diagrams have margins, expressed in pixels

Default value: 8

htmlLabels

Parameter	Description	Type	Required	Values
htmlLabels	Flag for setting whether or not a html tag should be used for rendering labels on the edges.	boolean	Required	true, false

Notes: Default value: true.

nodeSpacing

Parameter	Description	Type	Required	Values
nodeSpacing	Defines the spacing between nodes on the same level	Integer	Required	Any positive Number

Notes:

Pertains to horizontal spacing for TB (top to bottom) or BT (bottom to top) graphs, and the vertical spacing for LR as well as RL graphs.**

Default value: 50

rankSpacing

Parameter	Description	Type	Required	Values
rankSpacing	Defines the spacing between nodes on different levels	Integer	Required	Any Positive Number

Notes:

Pertains to vertical spacing for TB (top to bottom) or BT (bottom to top), and the horizontal spacing for LR as well as RL graphs.

Default value 50

curve

Parameter	Description	Type	Required	Values
curve	Defines how mermaid renders curves for flowcharts.	string	Required	'basis', 'linear', 'cardinal'

Notes:

Default Value: 'basis'

useMaxWidth

Parameter	Description	Type	Required	Values
useMaxWidth	See notes	boolean	4	true, false

Notes:

When this flag is set the height and width is set to 100% and is then scaling with the available space if not the absolute space required is used.

Default value: true

defaultRenderer

Parameter	Description	Type	Required	Values
defaultRenderer	See notes	boolean	4	dagre-d3, dagre-wrapper

Notes:

Decides which rendering engine that is to be used for the rendering. Legal values are: dagre-d3 dagre-wrapper - wrapper for dagre implemented in mermaid

Default value: 'dagre-d3'

sequence

The object containing configurations specific for sequence diagrams

activationWidth

Parameter	Description	Type	Required	Values
activationWidth	Width of the activation rect	Integer	Required	Any Positive Value

Notes: Default value :10

diagramMarginX

Parameter	Description	Type	Required	Values
diagramMarginX	Margin to the right and left of the sequence diagram	Integer	Required	Any Positive Value

Notes: Default value: 50

diagramMarginY

Parameter	Description	Type	Required	Values
diagramMarginY	Margin to the over and under the sequence diagram	Integer	Required	Any Positive Value

Notes: Default value: 10

actorMargin

Parameter	Description	Type	Required	Values
actorMargin	Margin between actors	Integer	Required	Any Positive Value

Notes: Default value: 50

width

Parameter	Description	Type	Required	Values
width	Width of actor boxes	Integer	Required	Any Positive Value

Notes: Default value: 150

height

Parameter	Description	Type	Required	Values
height	Height of actor boxes	Integer	Required	Any Positive Value

Notes: Default value: 65

boxMargin

Parameter	Description	Type	Required	Values
boxMargin	Margin around loop boxes	Integer	Required	Any Positive Value

Notes: Default value: 10

boxTextMargin

Parameter	Description	Type	Required	Values
boxTextMargin	Margin around the text in loop/alt/opt boxes	Integer	Required	Any Positive Value

Notes: Default value: 5

noteMargin

Parameter	Description	Type	Required	Values
noteMargin	margin around notes	Integer	Required	Any Positive Value

Notes: Default value: 10

messageMargin

Parameter	Description	Type	Required	Values
messageMargin	Space between messages	Integer	Required	Any Positive Value

Notes: Default value: 35

messageAlign

Parameter	Description	Type	Required	Values
messageAlign	Multiline message alignment	string	Required	'left', 'center', 'right'

Notes: Default value: 'center'

mirrorActors

Parameter	Description	Type	Required	Values
mirrorActors	Mirror actors under diagram	boolean	Required	true, false

Notes: Default value: true

forceMenus

Parameter	Description	Type	Required	Values
forceMenus	forces actor popup menus to always be visible (to support E2E testing).	Boolean	Required	True, False

Notes:

Default value: false.

bottomMarginAdj

Parameter	Description	Type	Required	Values
bottomMarginAdj	Prolongs the edge of the diagram downwards	Integer	Required	Any Positive Value

Notes:

Depending on css styling this might need adjustment.

Default value: 1

useMaxWidth

Parameter	Description	Type	Required	Values
useMaxWidth	See Notes	boolean	Required	true, false

Notes: When this flag is set to true, the height and width is set to 100% and is then scaling with the available space. If set to false, the absolute space required is used.

Default value: true

rightAngles

Parameter	Description	Type	Required	Values
rightAngles	display curve arrows as right angles	boolean	Required	true, false

Notes:

This will display arrows that start and begin at the same node as right angles, rather than a curve

Default value: false

showSequenceNumbers

Parameter	Description	Type	Required	Values
showSequenceNumbers	This will show the node numbers	boolean	Required	true, false

Notes: Default value: false

actorFontSize

Parameter	Description	Type	Required	Values
actorFontSize	This sets the font size of the actor's description	Integer	Require	Any Positive Value

Notes: Default value 14..

actorFontFamily

Parameter	Description	Type	Required	Values
actorFontFamily	This sets the font family of the actor's description	string	Required	Any Possible CSS FontFamily

Notes: Default value: "'Open Sans", sans-serif'

actorFontWeight

This sets the font weight of the actor's description

Notes: Default value: 400.

noteFontSize

Parameter	Description	Type	Required	Values
noteFontSize	This sets the font size of actor-attached notes	Integer	Required	Any Positive Value

Notes: Default value: 14

noteFontFamily

Parameter	Description	Type	Required	Values
noteFontFamily	This sets the font family of actor-attached notes.	string	Required	Any Possible CSS FontFamily

Notes: Default value: ''"trebuchet ms", verdana, arial, sans-serif'

noteFontWeight

This sets the font weight of the note's description

Notes: Default value: 400

noteAlign

Parameter	Description	Type	Required	Values
noteAlign	This sets the text alignment of actor-attached notes	string	required	'left', 'center', 'right'

Notes: Default value: 'center'

messageFontSize

Parameter	Description	Type	Required	Values
messageFontSize	This sets the font size of actor messages	Integer	Required	Any Positive Number

Notes: Default value: 16

messageFontFamily

Parameter	Description	Type	Required	Values
messageFontFamily	This sets the font family of actor messages	string	Required	Any Possible CSS FontFamily

Notes: Default value: '"trebuchet ms", verdana, arial, sans-serif'

messageFontWeight

This sets the font weight of the message's description

Notes: Default value: 400.

wrap

This sets the auto-wrap state for the diagram

Notes: Default value: false.

wrapPadding

This sets the auto-wrap padding for the diagram (sides only)

Notes: Default value: 0.

labelBoxWidth

This sets the width of the loop-box (loop, alt, opt, par)

Notes: Default value: 50.

labelBoxHeight

This sets the height of the loop-box (loop, alt, opt, par)

Notes: Default value: 20.

gantt

The object containing configurations specific for gantt diagrams

titleTopMargin

Parameter	Description	Type	Required	Values
titleTopMargin	Margin top for the text over the gantt diagram	Integer	Required	Any Positive Value

Notes: Default value: 25

barHeight

Parameter	Description	Type	Required	Values
barHeight	The height of the bars in the graph	Integer	Required	Any Positive Value

Notes: Default value: 20

barGap

Parameter	Description	Type	Required	Values
barGap	The margin between the different activities in the gantt diagram	Integer	Optional	Any Positive Value

Notes: Default value: 4

topPadding

Parameter	Description	Type	Required	Values
topPadding	Margin between title and gantt diagram and between axis and gantt diagram.	Integer	Required	Any Positive Value

Notes: Default value: 50

rightPadding

Parameter	Description	Type	Required	Values
rightPadding	The space allocated for the section name to the right of the activities	Integer	Required	Any Positive Value

Notes: Default value: 75

leftPadding

Parameter	Description	Type	Required	Values
leftPadding	The space allocated for the section name to the left of the activities	Integer	Required	Any Positive Value

Notes: Default value: 75

gridLineStartPadding

Parameter	Description	Type	Required	Values
gridLineStartPadding	Vertical starting position of the grid lines	Integer	Required	Any Positive Value

Notes: Default value: 35

sectionFontSize

Parameter	Description	Type	Required	Values
sectionFontSize	Font size for sections	Integer	Required	Any Positive Value

Notes: Default value: 11

numberSectionStyles

Parameter	Description	Type	Required	Values
numberSectionStyles	The number of alternating section styles	Integer	4	Any Positive Value

Notes: Default value: 4

axisFormat

Parameter	Description	Type	Required	Values
axisFormat	Datetime format of the axis	3	Required	Date in yy-mm-dd

Notes:

This might need adjustment to match your locale and preferences

Default value: '%Y-%m-%d'.

useMaxWidth

Parameter	Description	Type	Required	Values
useMaxWidth	See notes	boolean	4	true, false

Notes:

When this flag is set the height and width is set to 100% and is then scaling with the available space if not the absolute space required is used.

Default value: true

topAxis

Parameter	Description	Type	Required	Values
topAxis	See notes	Boolean	4	True, False

Notes: when this flag is set date labels will be added to the top of the chart

Default value false.

journey

The object containing configurations specific for journey diagrams

diagramMarginX

Parameter	Description	Type	Required	Values
diagramMarginX	Margin to the right and left of the sequence diagram	Integer	Required	Any Positive Value

Notes: Default value: 50

diagramMarginY

Parameter	Description	Type	Required	Values
diagramMarginY	Margin to the over and under the sequence diagram.	Integer	Required	Any Positive Value

Notes: Default value: 10

leftMargin

Parameter	Description	Type	Required	Values
actorMargin	Margin between actors	Integer	Required	Any Positive Value

Notes: Default value: 50

width

Parameter	Description	Type	Required	Values
width	Width of actor boxes	Integer	Required	Any Positive Value

Notes: Default value: 150

height

Parameter	Description	Type	Required	Values
height	Height of actor boxes	Integer	Required	Any Positive Value

Notes: Default value: 65

boxMargin

Parameter	Description	Type	Required	Values
boxMargin	Margin around loop boxes	Integer	Required	Any Positive Value

Notes: Default value: 10

boxTextMargin

Parameter	Description	Type	Required	Values
boxTextMargin	Margin around the text in loop/alt/opt boxes	Integer	Required	Any Positive Value

Notes: Default value: 5

noteMargin

Parameter	Description	Type	Required	Values
noteMargin	Margin around notes	Integer	Required	Any Positive Value

Notes: Default value: 10

messageMargin

Parameter	Description	Type	Required	Values
messageMargin	Space between messages.	Integer	Required	Any Positive Value

Notes:

Space between messages.

Default value: 35

messageAlign

Parameter	Description	Type	Required	Values
messageAlign	Multiline message alignment	3	4	'left', 'center', 'right'

Notes: Default value: 'center'

bottomMarginAdj

Parameter	Description	Type	Required	Values
bottomMarginAdj	Prolongs the edge of the diagram downwards	Integer	4	Any Positive Value

Notes:

Depending on css styling this might need adjustment.

Default value: 1

useMaxWidth

Parameter	Description	Type	Required	Values
useMaxWidth	See notes	boolean	4	true, false

Notes:

When this flag is set the height and width is set to 100% and is then scaling with the available space if not the absolute space required is used.

Default value: true

rightAngles

Parameter	Description	Type	Required	Values
rightAngles	Curved Arrows become Right Angles	3	4	true, false

Notes:

This will display arrows that start and begin at the same node as right angles, rather than a curves

Default value: false

useMaxWidth

Parameter	Description	Type	Required	Values
useMaxWidth	See notes	boolean	4	true, false

Notes:

When this flag is set the height and width is set to 100% and is then scaling with the available space if not the absolute space required is used.

Default value: true

defaultRenderer

Parameter	Description	Type	Required	Values
defaultRenderer	See notes	boolean	4	dagre-d3, dagre-wrapper

Notes:

Decides which rendering engine that is to be used for the rendering. Legal values are: dagre-d3 dagre-wrapper - wrapper for dagre implemented in mermaid

Default value: 'dagre-d3'

useMaxWidth

Parameter	Description	Type	Required	Values
useMaxWidth	See notes	boolean	4	true, false

Notes:

When this flag is set the height and width is set to 100% and is then scaling with the available space if not the absolute space required is used.

Default value: true

defaultRenderer

Parameter	Description	Type	Required	Values
defaultRenderer	See notes	boolean	4	dagre-d3, dagre-wrapper

Notes:

Decides which rendering engine that is to be used for the rendering. Legal values are: dagre-d3 dagre-wrapper - wrapper for dagre implemented in mermaid

Default value: 'dagre-d3'

er

The object containing configurations specific for entity relationship diagrams

diagramPadding

Parameter	Description	Type	Required	Values
diagramPadding	Amount of padding around the diagram as a whole	Integer	Required	Any Positive Value

Notes:

The amount of padding around the diagram as a whole so that embedded diagrams have margins, expressed in pixels

Default value: 20

layoutDirection

Parameter	Description	Type	Required	Values
layoutDirection	Directional bias for layout of entities.	string	Required	"TB", "BT", "LR", "RL"

Notes:

'TB' for Top-Bottom, 'BT'for Bottom-Top, 'LR' for Left-Right, or 'RL' for Right to Left.

T = top, B = bottom, L = left, and R = right.

Default value: 'TB'

minEntityWidth

Parameter	Description	Type	Required	Values
minEntityWidth	The minimum width of an entity box	Integer	Required	Any Positive Value

Notes: Expressed in pixels. Default value: 100

minEntityHeight

Parameter	Description	Type	Required	Values
minEntityHeight	The minimum height of an entity box	Integer	4	Any Positive Value

Notes: Expressed in pixels Default value: 75

entityPadding

Parameter	Description	Type	Required	Values
entityPadding	Minimum internal padding betweentext in box and box borders	Integer	4	Any Positive Value

Notes:

The minimum internal padding betweentext in an entity box and the enclosing box borders, expressed in pixels.

Default value: 15

stroke

Parameter	Description	Type	Required	Values
stroke	Stroke color of box edges and lines	string	4	Any recognized color

Notes: Default value: 'gray'

fill

Parameter	Description	Type	Required	Values
fill	Fill color of entity boxes	string	4	Any recognized color

Notes: Default value: 'honeydew'

useMaxWidth

Parameter	Description	Type	Required	Values
useMaxWidth	See Notes	boolean	Required	true, false

Notes:

When this flag is set to true, the diagram width is locked to 100% and scaled based on available space. If set to false, the diagram reserves its absolute width.

Default value: true

pie

The object containing configurations specific for pie diagrams

useMaxWidth

Parameter	Description	Type	Required	Values
useMaxWidth	See Notes	boolean	Required	true, false

Notes:

When this flag is set to true, the diagram width is locked to 100% and scaled based on available space. If set to false, the diagram reserves its absolute width.

Default value: true

requirement

The object containing configurations specific for req diagrams

useMaxWidth

Parameter	Description	Type	Required	Values
useMaxWidth	See Notes	boolean	Required	true, false

Notes:

When this flag is set to true, the diagram width is locked to 100% and scaled based on available space. If set to false, the diagram reserves its absolute width.

Default value: true

setSiteConfig

Function	Description	Type	Values
setSiteConfig	Sets the siteConfig to desired values	Put Request	Any Values, except ones in secure array

Notes: Sets the siteConfig. The siteConfig is a protected configuration for repeat use. Calls to reset() will reset the currentConfig to siteConfig. Calls to reset(configApi.defaultConfig) will reset siteConfig and currentConfig to the defaultConfig Note: currentConfig is set in this function Default value: At default, will mirror Global Config

Parameters

conf The base currentConfig to use as siteConfig

Returns object The siteConfig

parse

Parameters

text

Returns any

getSiteConfig

Function	Description	Type	Values
setSiteConfig	Returns the current siteConfig base configuration	Get Request	Returns Any Values in siteConfig

Notes: Returns any values in siteConfig.

Returns object The siteConfig

setConfig

Function	Description	Type	Values
setSiteConfig	Sets the siteConfig to desired values	Put Request	Any Values, except ones in secure array

Notes: Sets the currentConfig. The parameter conf is sanitized based on the siteConfig.secure keys. Any values found in conf with key found in siteConfig.secure will be replaced with the corresponding siteConfig value.

Parameters

conf any The potential currentConfig

Returns any The currentConfig merged with the sanitized conf

getConfig

Function	Description	Type	Return Values
getConfig	Obtains the currentConfig	Get Request	Any Values from current Config

Notes: Returns any the currentConfig

Returns any The currentConfig

sanitize

Function	Description	Type	Values
sanitize	Sets the siteConfig to desired values.	Put Request	None

Ensures options parameter does not attempt to override siteConfig secure keys Notes: modifies options in-place

Parameters

options any The potential setConfig parameter

addDirective

Pushes in a directive to the configuration

Parameters

directive object The directive to push in

reset

Function	Description	Type	Required	Values
reset	Resets currentConfig to conf	Put Request	Required	None

conf

Parameter	Description	Type	Required	Values
conf	base set of values, which currentConfig coul be reset to.	Dictionary	Required	Any Values, with respect to the secure Array

Notes: (default: current siteConfig ) (optional, default getSiteConfig())

render

Function that renders an SVG with a graph from a chart definition. Usage example below.

mermaidAPI.initialize({
  startOnLoad: true,
});
$(function () {
  const graphDefinition = 'graph TB\na-->b';
  const cb = function (svgGraph) {
    console.log(svgGraph);
  };
  mermaidAPI.render('id1', graphDefinition, cb);
});

Parameters

id any The id of the element to be rendered
_txt any The graph definition
cb any Callback which is called after rendering is finished with the SVG code as inparam.
container any Selector to element in which a div with the graph temporarily will be inserted. In one is provided a hidden div will be inserted in the body of the page instead. The element will be removed when rendering is completed.

Returns any

updateRendererConfigs

Parameters

conf any

reinitialize

To be removed

initialize

Parameters

options any

mermaidAPI configuration defaults

<script>
  var config = {
    theme: 'default',
    logLevel: 'fatal',
    securityLevel: 'strict',
    startOnLoad: true,
    arrowMarkerAbsolute: false,

    er: {
      diagramPadding: 20,
      layoutDirection: 'TB',
      minEntityWidth: 100,
      minEntityHeight: 75,
      entityPadding: 15,
      stroke: 'gray',
      fill: 'honeydew',
      fontSize: 12,
      useMaxWidth: true,
    },
    flowchart: {
      diagramPadding: 8,
      htmlLabels: true,
      curve: 'basis',
    },
    sequence: {
      diagramMarginX: 50,
      diagramMarginY: 10,
      actorMargin: 50,
      width: 150,
      height: 65,
      boxMargin: 10,
      boxTextMargin: 5,
      noteMargin: 10,
      messageMargin: 35,
      messageAlign: 'center',
      mirrorActors: true,
      bottomMarginAdj: 1,
      useMaxWidth: true,
      rightAngles: false,
      showSequenceNumbers: false,
    },
    gantt: {
      titleTopMargin: 25,
      barHeight: 20,
      barGap: 4,
      topPadding: 50,
      leftPadding: 75,
      gridLineStartPadding: 35,
      fontSize: 11,
      fontFamily: '"Open Sans", sans-serif',
      numberSectionStyles: 4,
      axisFormat: '%Y-%m-%d',
      topAxis: false,
    },
  };
  mermaid.initialize(config);
</script>

Files

Setup.md

Latest commit

History

Setup.md

File metadata and controls

mermaidAPI

Configuration

What follows are config instructions for older versions

theme

fontFamily

logLevel

securityLevel

startOnLoad

arrowMarkerAbsolute

secure

deterministicIds

deterministicIDSeed

flowchart

diagramPadding

htmlLabels

nodeSpacing

rankSpacing

curve

useMaxWidth

defaultRenderer

sequence

activationWidth

diagramMarginX

diagramMarginY

actorMargin

width

height

boxMargin

boxTextMargin

noteMargin

messageMargin

messageAlign

mirrorActors

forceMenus

bottomMarginAdj

useMaxWidth

rightAngles

showSequenceNumbers

actorFontSize

actorFontFamily

actorFontWeight

noteFontSize

noteFontFamily

noteFontWeight

noteAlign

messageFontSize

messageFontFamily

messageFontWeight

wrap

wrapPadding

labelBoxWidth

labelBoxHeight

gantt

titleTopMargin

titleTopMargin

barHeight

barGap

topPadding

rightPadding

leftPadding

gridLineStartPadding

fontSize

sectionFontSize

numberSectionStyles

axisFormat

useMaxWidth

topAxis

journey

diagramMarginX

diagramMarginY

leftMargin

width

height

boxMargin