I have a dynamic form that is building and rebuilding categories based on the users input. Basically it is a product finder that narrows down the results as more categories are checked. I am mostly doing this with jQuery, but I found this piece of code that takes the form data and turns it into JSON.

var fData = new FormData(document.querySelector('#prodFilter'))
// Build Filters
buildFilterData(fData);


function buildFilterData(e) {
    const object = {};
    e.forEach((value, key) => {
        // Reflect.has in favor of: object.hasOwnProperty(key)
        if(!Reflect.has(object, key)){
            object[key] = value;
            return;
        }
        if(!Array.isArray(object[key])){
            obFOrject[key] = [object[key]];    
        }
        object[key].push(value);
    });

    // Stringify Result
    let formResult = JSON.stringify(object);
    params = formResult;
    return params;
}

This little snippet is cool because it can handle multiple checked values. I get a result like:

{"keyword":"","product_type":"Category","product_category":["Sub-Cat1","Sub-Cat2"]}

This is/was working great until I tried to add a keyword search box to further narrow-down results within the selected categories. As soon as I try and populate that text input it drops all the checkbox data (the categories are still checked). I am logging my parameters as the form is submitted and I get something like this:

{"keyword":"ER 8"}

The weird part is that if I type a keyword into the box, then start checking categories it picks up all the data and I get:

{"keyword":"ER 8","product_type":"Category","product_category":["Sub-Cat1","Sub-Cat2"]}

Anyone have any idea why the checkbox/radio fields are being dropped? Hopefully I have provided plenty of information, I'm happy to clarify anything I can.