how to call a event in the dialogflow v2 :nodejs - node.js

Question

I'm using dialogflow v2 using npm. I just want call a welcome event in dialogflow. How can I do it in the nodejs. I'm pretty new to it.
This is my code
const projectId = "xxxxxx";
const LANGUAGE_CODE = 'en-US';
const sessionId = req.body.sessionId;
var query = req.body.query;
const sessionClient = new dialogflow.SessionsClient();
const sessionPath = sessionClient.sessionPath(projectId,sessionId);
const request = {
session: sessionPath,
queryInput: {
text: {
text: query,
languageCode: LANGUAGE_CODE,
},
},
};
sessionClient.detectIntent(request).then(response => {
console.log('intent detected');
const result = response[0].queryResult;
console.log(` Query: ${result.queryText}`);
console.log(` Response: ${result.fulfillmentText}`);
if(result.fulfillmentText) {
console.log(result.fulfillmentText);
return res.json({reply: result.fulfillmentText})
}
// if(result.intent) {
// console.log(` Intent: ${result.intent.displayName}`)
// }
else {
console.log('no intent found');
}
}).catch(err => {
console.log('error '+err);
})
As I open the chat page I just want to throw a welcome message. In order to do that, i read that i have to call the event. How can I do that? I have taken the reference from here

Answer 1

The Request body should be like this:
let eventName='WELCOME'; //name of the event
let request = {
session: sessionPath,
queryInput: {
event: {
name: eventName,
languageCode: 'en-US'
},
},
};
checkout- https://github.com/googleapis/nodejs-dialogflow/blob/master/samples/detect.js#L96
let me know if you find any difficulties :)

Answer 2

I would suggest using actions-on-google as it is much easier to build nodejs backend for dialogflow link : actions on google
And for sample project refer Number genie project
Hope this would help you.