Edge

Connect nodes in sequence or branch conditionally. Use START and END for graph boundaries.

Basics

• From: a node id or START
• To: a node id, END, a function (state) => nextId, or a JSON-based router object

Simple Edges

// Linear flow
.addEdge(START, 'ask')
.addEdge('ask', 'reply')
.addEdge('reply', END)

Function-based Routing

Use a function to determine the next node based on state:

// Conditional routing with function
.addEdge('choose', (state) => (state.isAdmin ? 'admin_node' : 'user_node'))

JSON-based Routing

Define conditional routing using JSON configuration for fully serializable graphs

• conditions:
  • field: state field to check
  • operator: comparison operator (see below)
  • value: value to compare against
  • goto: target node id if condition matches
• default: target node id if all conditions fail

// JSON-based conditional routing
.addEdge('ask_age', {
  conditions: [
    { field: 'age', operator: 'lt', value: 18, goto: 'minor_node' },
    { field: 'age', operator: 'gte', value: 65, goto: 'senior_node' },
  ],
  default: 'adult_node'
})

Available Operators

• Equality: equals, not_equals
• Comparison: gt (>), gte (≥), lt (<), lte (≤)
• String/Array: contains, not_contains
• Regular Expression: regex
• Membership: in, not_in

Examples

Numeric comparison:

{
  conditions: [
    { field: 'score', operator: 'gte', value: 90, goto: 'excellent' },
    { field: 'score', operator: 'gte', value: 70, goto: 'good' },
    { field: 'score', operator: 'gte', value: 50, goto: 'fair' },
  ],
  default: 'poor'
}

String matching:

{
  conditions: [
    { field: 'message', operator: 'contains', value: 'hello', goto: 'greeting' },
    { field: 'message', operator: 'regex', value: '^help', goto: 'help' },
  ],
  default: 'other'
}

Membership check:

{
  conditions: [
    { field: 'color', operator: 'in', value: ['red', 'blue', 'yellow'], goto: 'primary' },
  ],
  default: 'not_primary'
}

Condition Evaluation

Conditions are evaluated in order, and the first matching condition determines the route. If no conditions match, the default route is used.