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JavaScript / Firestore .set() method - setting an array saved to a variable

Hi, I'm using Firestore's .set() method to create a new document.

To save data in an array format, it needs to be set out like this: arrayExample: [5, true, "hello"]

I have an array of strings saved to a variable (urlsArray) that I want to pass in here, and I have tried all of the following formats:

arrayExample: urlsArray (empty array is saved to Firestore doc - data from urlsArray is not passed in)

arrayExample: [urlsArray] (Firestore error: nested arrays not supported)

arrayExample: urlsArray[0], urlsArray[1], urlsArray[2] (syntax error in text editor after first value)

arrayExample: [urlsArray[0], urlsArray[1], urlsArray[2]] (Firestore error: unsupported field type)

Can anyone suggest how I can pass in the data from my array and save it in the correct Firestore array format?

Here is my code snippet (which currently uploads an empty array to Firestore):

 * Listens for submit on `#addItemsForm`;
 * Adds new document to Firestore with form input data;
 * Calls addItemToStock() on stock object using Firestore document data.
addItemsForm.addEventListener('submit', function(e){
    var itemNo = addItemsForm.itemNo.value;
        //used firestore .set() method to add in data-id 
        //can use firestore .add() method for auto-generated data-id
            name: addItemsForm.name.value,
            description: addItemsForm.description.value,
            itemNo: addItemsForm.itemNo.value,
            size: addItemsForm.size.value,
            price: Number(addItemsForm.price.value),
            orderTotal: Number(addItemsForm.orderTotal.value),
            imageURLs: urlsArray
        }).then(function() {
            console.log('New doc successfully added to Firestore');
            // clearForm();
            // window.location.reload();
            console.log("Error: " + reason);