How to comsume data from a sse server in Nodejs?

I have a server that emits data at regular intervals of time. I want to use this data in my rest API, How do I fetch it? It needs to be automatically called when the data is pushed from that external source. I have tried the following but it did not work.

var EventSource = require("eventsource");

var url = "..." // Source URL
    var es =  new EventSource(url);
    es.onmessage = (event) => {
        console.log(event)
        const parsedData = JSON.parse(event.data);
        console.log(parsedData)
    }

Any help is appreciated.

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