/**
* JSONata extensions for execution history access
*/
import jsonata from "jsonata";
import { logger } from "../logger.js";
import type { NodeExecutionRecord } from "../types/execution.js";
/**
* Register custom JSONata functions for history access
*/
export function registerHistoryFunctions(
expr: jsonata.Expression,
history: NodeExecutionRecord[],
currentIndex: number
): void {
// $previousNode() - returns previous node's output
// $previousNode(index) - returns node that executed N steps before current
expr.registerFunction(
"previousNode",
(offset?: number) => {
const stepsBack = offset !== undefined ? offset : 1;
const targetIndex = currentIndex - stepsBack;
if (targetIndex < 0 || targetIndex >= history.length) {
logger.debug(`$previousNode(${stepsBack}): No node at index ${targetIndex}`);
return null;
}
const record = history[targetIndex];
logger.debug(`$previousNode(${stepsBack}) returning output from node: ${record.nodeId} (index ${targetIndex})`);
return record.output;
},
"<n?:o>" // Optional number argument, returns object
);
// $executionCount(nodeName) - count of executions for a node
expr.registerFunction(
"executionCount",
(nodeName: string) => {
if (typeof nodeName !== "string") {
return 0;
}
const count = history.filter(r => r.nodeId === nodeName).length;
logger.debug(`$executionCount("${nodeName}") = ${count}`);
return count;
},
"<s:n>" // String argument, returns number
);
// $nodeExecution(nodeName, index) - specific execution by index (0 = first, -1 = last)
expr.registerFunction(
"nodeExecution",
(nodeName: string, index: number) => {
if (typeof nodeName !== "string" || typeof index !== "number") {
return null;
}
const executions = history.filter(r => r.nodeId === nodeName);
if (executions.length === 0) {
logger.debug(`$nodeExecution("${nodeName}", ${index}): No executions found`);
return null;
}
// Handle negative indices (from end)
let actualIndex = index;
if (index < 0) {
actualIndex = executions.length + index;
}
if (actualIndex < 0 || actualIndex >= executions.length) {
logger.debug(`$nodeExecution("${nodeName}", ${index}): Index ${actualIndex} out of range`);
return null;
}
const record = executions[actualIndex];
logger.debug(`$nodeExecution("${nodeName}", ${index}) = execution at index ${actualIndex}`);
return record.output;
},
"<s-n:o>" // String and number arguments, returns object
);
// $nodeExecutions(nodeName) - array of all executions for a node
expr.registerFunction(
"nodeExecutions",
(nodeName: string) => {
if (typeof nodeName !== "string") {
return [];
}
const executions = history.filter(r => r.nodeId === nodeName);
const outputs = executions.map(r => r.output);
logger.debug(`$nodeExecutions("${nodeName}") = ${executions.length} executions`);
return outputs;
},
"<s:a>" // String argument, returns array
);
}
