You cannot directly insert a string to a collection. The insert method expects a document which is of type object.
Try this instead -
FooterButtons.insert({ text: buttonsList[i] });
Also, I notice that you are trying to clear your FooterButtons collection. Please note that you cannot clear a collection like this from the client side as it is considered untrusted code. From client side, you can only remove one document at a time, specified by its _id.
I would recommend you to use a method instead.
Meteor.methods({
replaceCollectionContents: function (buttonsList) {
// remove all existing documents in the collection
FooterButtons.remove({});
// insert new button documents into the collection
buttonsList.forEach(function (button) {
FooterButtons.insert({ text: button });
});
}
});
And call this method when needed
Meteor.call("replaceCollectionContents", ['NO', 'B', 'YES']);
Inside the method, note that I'm passing a {} selector to the remove method because for safety reasons, Meteor does not remove any documents if selector is omitted.
You can read more about remove in Meteor docs.