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Every node in a JDM file has a type that determines its behavior and content structure.

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Available node types

TypeDescription
inputNodeEntry point for decision input
outputNodeExit point returning the result
decisionTableNodeSpreadsheet-style conditional logic
expressionNodeZEN expression transformations
functionNodeCustom JavaScript logic
switchNodeConditional branching
decisionNodeSub-decision reference

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Common node properties

All nodes share these properties:
PropertyTypeDescription
idstringUnique identifier
typestringNode type
namestringDisplay name
positionobjectCanvas position { x, y }
contentobjectType-specific configuration

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Input node

The entry point for every decision. Receives the data you pass to evaluate(). 
{
  "id": "input",
  "type": "inputNode",
  "name": "Request",
  "position": { "x": 0, "y": 100 },
  "content": {
    "schema": ""
  }
}
PropertyTypeDescription
schemastringOptional JSON Schema for input validation

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Output node

The exit point that returns the decision result. 
{
  "id": "output",
  "type": "outputNode",
  "name": "Response",
  "position": { "x": 600, "y": 100 },
  "content": {
    "schema": ""
  }
}
PropertyTypeDescription
schemastringOptional JSON Schema for output validation

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Decision table node

Spreadsheet-style conditional logic with inputs, outputs, and rules. 
{
  "type": "decisionTableNode",
  "content": {
    "hitPolicy": "first",
    "inputs": [
      { "id": "i1", "name": "Customer Tier", "field": "customer.tier" },
      { "id": "i2", "name": "Order Total", "field": "order.total" }
    ],
    "outputs": [
      { "id": "o1", "name": "Discount", "field": "discount" }
    ],
    "rules": [
      { "_id": "r1", "i1": "\"gold\"", "i2": ">= 100", "o1": "0.15" },
      { "_id": "r2", "i1": "", "i2": "", "o1": "0" }
    ],
    "passThrough": true,
    "inputField": null,
    "outputPath": null,
    "executionMode": "single"
  }
}

​
Content properties

PropertyTypeDefaultDescription
hitPolicy"first" | "collect""first"Return first match or all matches
inputsarrayInput column definitions
outputsarrayOutput column definitions
rulesarrayRule rows (keyed by column id)
passThroughbooleantrueInclude input data in output
inputFieldstring | nullnullArray field to iterate (for loop mode)
outputPathstring | nullnullPath to store output
executionMode"single" | "loop""single"Process once or iterate array

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Input column

PropertyTypeDescription
idstringUnique identifier (used in rules)
namestringDisplay label
fieldstringPath to input value (enables unary mode)
defaultValuestringDefault if field is null

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Output column

PropertyTypeDescription
idstringUnique identifier (used in rules)
namestringDisplay label
fieldstringOutput field name
defaultValuestringDefault if no rule matches

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Rules format

Each rule is an object with _id and entries keyed by column id: 
{ "_id": "rule-1", "i1": ">= 100", "i2": "\"gold\"", "o1": "0.15" }
Leave a cell empty ("") to match any value.

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Expression node

Transform data using ZEN expressions. 
{
  "type": "expressionNode",
  "content": {
    "expressions": [
      { "id": "e1", "key": "subtotal", "value": "sum(map(items, #.price * #.qty))" },
      { "id": "e2", "key": "tax", "value": "$.subtotal * 0.08" },
      { "id": "e3", "key": "total", "value": "$.subtotal + $.tax" }
    ],
    "passThrough": true,
    "inputField": null,
    "outputPath": null,
    "executionMode": "single"
  }
}

​
Content properties

PropertyTypeDefaultDescription
expressionsarrayKey-value expression pairs
passThroughbooleantrueInclude input data in output
inputFieldstring | nullnullArray field to iterate (for loop mode)
outputPathstring | nullnullPath to store output
executionMode"single" | "loop""single"Process once or iterate array

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Expression entry

PropertyTypeDescription
idstringUnique identifier
keystringOutput field name
valuestringZEN expression
Use $ to reference values calculated earlier in the same node.

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Function node

Custom JavaScript for complex logic. 
{
  "type": "functionNode",
  "content": {
    "source": "/** @type {Handler} */\nexport const handler = async (input) => {\n  return { loyaltyPoints: Math.floor(input.total * 1.5) };\n}"
  }
}
PropertyTypeDescription
sourcestringJavaScript function code
Function nodes support:
  • ES6+ JavaScript syntax
  • async/await for asynchronous operations
  • Built-in libraries: dayjs, big.js, zod

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Switch node

Route data through different paths based on conditions. 
{
  "type": "switchNode",
  "content": {
    "hitPolicy": "first",
    "statements": [
      { "id": "s1", "condition": "customer.tier == 'enterprise'", "isDefault": false },
      { "id": "s2", "condition": "customer.tier == 'business'", "isDefault": false },
      { "id": "s3", "condition": "", "isDefault": true }
    ]
  }
}

​
Content properties

PropertyTypeDefaultDescription
hitPolicy"first" | "collect""first"Execute first match or all matches
statementsarrayBranch conditions

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Statement

PropertyTypeDescription
idstringUnique identifier (used as edge sourceHandle)
conditionstringZEN expression evaluating to boolean
isDefaultbooleanTrue for the fallback branch

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Connecting switch outputs

Each statement id becomes a source handle for edges: 
{
  "edges": [
    { "id": "e1", "sourceId": "switch-1", "targetId": "enterprise-node", "sourceHandle": "s1", "type": "edge" },
    { "id": "e2", "sourceId": "switch-1", "targetId": "business-node", "sourceHandle": "s2", "type": "edge" },
    { "id": "e3", "sourceId": "switch-1", "targetId": "default-node", "sourceHandle": "s3", "type": "edge" }
  ]
}

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Decision node

Reference another decision (sub-decision). 
{
  "type": "decisionNode",
  "content": {
    "key": "pricing/calculate-discount",
    "passThrough": true,
    "inputField": null,
    "outputPath": null,
    "executionMode": "single"
  }
}
PropertyTypeDefaultDescription
keystringPath to the referenced decision
passThroughbooleantrueInclude input data in output
inputFieldstring | nullnullArray field to iterate (for loop mode)
outputPathstring | nullnullPath to store output
executionMode"single" | "loop""single"Process once or iterate array

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Edge schema

Edges connect nodes in the graph: 
{
  "id": "edge-1",
  "sourceId": "node-a",
  "targetId": "node-b",
  "sourceHandle": null,
  "type": "edge"
}
PropertyTypeDescription
idstringUnique identifier
sourceIdstringSource node id
targetIdstringTarget node id
sourceHandlestring | nullOutput handle (for switch nodes)
type"edge"Always “edge”