How to display data from another source in Javascript

I am trying to wrap my head around this. I just started learning javascript. Basically on my site, I have a plugin/script that asks the user a bunch of questions and at the end, it asks for their email address. I am using emailjs to send the info (well that’s what I am trying to do) but can’t figure out the proper javascript code.

In the code, if I put my email address in the variable templateParams under to_name: The email gets sent when the user enters their email and I receive it but it’s blank with no data. I don’t know how to grab the data with the info below from the plugin documentation.

 onSendEmail: function(emailData) {
           // User clicked send button on share by email. You have to manage sending
           // the email yourself with the following data received in the parameter:
           console.log(emailData);
       /*
      {
        "data": {
          "cvData": [
            {
              "name": "overall",
              "value": 71,
              "feedback": "Excellent"
            },
            {
              "name": "smoothness",
              "value": 52,
              "tip": "Smoothness can be affected by using correct products.",
              "info": "Healthy skin is free of dryness, hyperpigmentation, ...",
              "feedback": "Good"
            },
            {
              "name": "radiance",
              "value": 73,
              "info": "Skin radiance is the glowy, vibrant look we ...",
              "feedback": "Excellent"
            },
            ...
          ],
          "products": {
            "morning": {
              "highend": [{product1},{product2},{product3}],
              "economy": [{product4}, {product5}, {product6}],
              "standard": [{product7}, {product8}, {product9}]
            },
            "evening": {
              "highend": [{product1},{product2},{product3}],
              "economy": [{product4}, {product5}, {product6}],
              "standard": [{product7}, {product8}, {product9}]
            }
          },
          "activeRoutine": "evening",
          "activePriceGroup": "standard",
          "activeFilters": {
            "skin_type": { "value": "normal" },
            "gender_ui": { "value": "female" },
            "age_ui": { "value": 31 },
            "eyebags_ui": { "value": 1 },
            "dull_tired_ui": { "value": 1 },
            "redness_ui": { "value": 1 },
            "lat": { "value": 39.47504 },
            "lon": { "value": -0.4117344 },
            "darkspots_ui": { "value": 1 },
            "wrinkles_ui": { "value": 1 }
          },
          "activeSelections": {
            "userAllowsCamera": true,
            "locationData": {
              "status": "done",
              "location": {
                "lat": 39.47504, "lon": -0.4117344,
                "city": "Valencia", "country": "Spain", "area": "Valencia",
                "uvIndex": 9, "pollution": 30, "humidity": 77
              }
            },
            "skin_type": "normal",
            "skin_concerns": ["dull_tired", "redness"],
            "eyebags": 1,
            "darkspots": 1,
            "wrinkles": 1,
            "gender": "female",
            "age": "31",
            "selfieSource": "video"
          },
        },
        "email": "[email protected]",
        "locale": "en",
        "partnerId": "XXXXXXX",
        ...
      }
      */
                
           let templateParams = {
            to_name: 'email',
            from_name: 'abc',
            message: 'random message'
            
          };

       emailjs.send('SERVICE_ID', 'TEMPLATE_ID', templateParams)
       .then(function(response) {
       console.log('SUCCESS!', response.status, response.text);
        }, function(error) {
       console.log('FAILED...', error);
       });
        }, 
       };