ILink

The ILink interface defines a dependency link between two tasks. Links are rendered as arrows on the Gantt chart and can represent four types of task relationships.

TypeScript definition

export interface ILink {
  id?: TID;
  source: TID;
  target: TID;
  type: TLinkType;
  lag?: number;
}

export type TLinkType = "s2s" | "s2e" | "e2s" | "e2e";
export type TID = string | number;

Fields

string | number

Unique identifier for the link. Auto-generated if omitted when adding a link via api.exec("add-link", ...).

string | number

required

ID of the predecessor (source) task — the task that the dependent task follows.

string | number

required

ID of the successor (target) task — the task that depends on the source.

s2s

required

The link type, describing which endpoints of the source and target tasks are connected. See Link types below.

number

A time offset in durationUnit units (days by default). A positive lag introduces a delay between the two tasks. A negative value represents lead time (overlap). Defaults to 0.

Link types

The four link types define the dependency relationship using the start (s) and end (e) points of the source and target tasks.

Type	Meaning	Description
`e2s`	End-to-Start	Target starts after source ends. The most common type.
`s2s`	Start-to-Start	Target starts when source starts.
`e2e`	End-to-End	Target ends when source ends.
`s2e`	Start-to-End	Target ends when source starts. Rarely used.

e2s (End-to-Start)       s2s (Start-to-Start)
[Source -------]         [Source -------]
               [Target--]  [Target------]

e2e (End-to-End)         s2e (Start-to-End)
[Source -------]             [Source -------]
        [Target-]  [Target--]

The default link type when creating a link by dragging in the UI is e2s.

Examples

End-to-Start link
With lag
Adding a link via API

const link: ILink = {
  id: 1,
  source: 10,
  target: 20,
  type: "e2s"
};

// Target task starts 2 days after source ends
const link: ILink = {
  id: 2,
  source: 10,
  target: 20,
  type: "e2s",
  lag: 2
};

api.exec("add-link", {
  link: {
    source: 10,
    target: 20,
    type: "e2s",
    lag: 0
  }
});

Components

Data Types

API Object

Data Provider

TypeScript definition

Fields

Link types

Examples

​TypeScript definition

​Fields

​Link types

​Examples

TypeScript definition

Fields

Link types

Examples