The example code is producing an error.

[Liang-Feifei]

I copied the example code for Exclusive Gateway, but it's generating an error when I try to run it. Could you please help me? thank you.

like this:

UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'input' of undefined

[paed01]

Do you pass input as a property to variables when executing the source? The sequence flows condition scripts requires property input.

[Liang-Feifei]

I directly used the source code from your Exclusive Gateway section。Do I need to pass input parameters elsewhere?

'use strict';

const {Engine} = require('bpmn-engine');
const {EventEmitter} = require('events');

const source = `
<?xml version="1.0" encoding="UTF-8"?>
<definitions xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <process id="theProcess" isExecutable="true">
    <startEvent id="start" />
    <exclusiveGateway id="decision" />
    <endEvent id="end1" />
    <endEvent id="end2" />
    <sequenceFlow id="flow1" sourceRef="start" targetRef="decision" />
    <sequenceFlow id="flow2" sourceRef="decision" targetRef="end1">
      <conditionExpression xsi:type="tFormalExpression" language="JavaScript"><![CDATA[
      next(null, this.environment.variables.input <= 50);
      ]]></conditionExpression>
    </sequenceFlow>
    <sequenceFlow id="flow3" sourceRef="decision" targetRef="end2">
      <conditionExpression xsi:type="tFormalExpression" language="JavaScript"><![CDATA[
      next(null, this.environment.variables.input > 50);
      ]]></conditionExpression>
    </sequenceFlow>
  </process>
</definitions>`;

const engine = new Engine({
  name: 'exclusive gateway example',
  source
});

const listener = new EventEmitter();

listener.on('activity.start', (api) => {
  if (api.id === 'end1') throw new Error(`<${api.id}> was not supposed to be taken, check your input`);
  if (api.id === 'end2') console.log(`<${api.id}> correct decision was taken`);
});

engine.execute({
  listener,
  variables: {
    input: 51
  }
});

engine.on('end', () => {
  console.log('completed');
});

[paed01]

What version of the engine are you using?

[Liang-Feifei]

Sorry, I might have missed a code snippet earlier. It's been resolved now, thank you.